Black Lives Matter. Support the Equal Justice Initiative.

Source file src/testing/testing.go

Documentation: testing

     1  // Copyright 2009 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // Package testing provides support for automated testing of Go packages.
     6  // It is intended to be used in concert with the "go test" command, which automates
     7  // execution of any function of the form
     8  //     func TestXxx(*testing.T)
     9  // where Xxx does not start with a lowercase letter. The function name
    10  // serves to identify the test routine.
    11  //
    12  // Within these functions, use the Error, Fail or related methods to signal failure.
    13  //
    14  // To write a new test suite, create a file whose name ends _test.go that
    15  // contains the TestXxx functions as described here. Put the file in the same
    16  // package as the one being tested. The file will be excluded from regular
    17  // package builds but will be included when the "go test" command is run.
    18  // For more detail, run "go help test" and "go help testflag".
    19  //
    20  // A simple test function looks like this:
    21  //
    22  //     func TestAbs(t *testing.T) {
    23  //         got := Abs(-1)
    24  //         if got != 1 {
    25  //             t.Errorf("Abs(-1) = %d; want 1", got)
    26  //         }
    27  //     }
    28  //
    29  // Benchmarks
    30  //
    31  // Functions of the form
    32  //     func BenchmarkXxx(*testing.B)
    33  // are considered benchmarks, and are executed by the "go test" command when
    34  // its -bench flag is provided. Benchmarks are run sequentially.
    35  //
    36  // For a description of the testing flags, see
    37  // https://golang.org/cmd/go/#hdr-Testing_flags
    38  //
    39  // A sample benchmark function looks like this:
    40  //     func BenchmarkRandInt(b *testing.B) {
    41  //         for i := 0; i < b.N; i++ {
    42  //             rand.Int()
    43  //         }
    44  //     }
    45  //
    46  // The benchmark function must run the target code b.N times.
    47  // During benchmark execution, b.N is adjusted until the benchmark function lasts
    48  // long enough to be timed reliably. The output
    49  //     BenchmarkRandInt-8   	68453040	        17.8 ns/op
    50  // means that the loop ran 68453040 times at a speed of 17.8 ns per loop.
    51  //
    52  // If a benchmark needs some expensive setup before running, the timer
    53  // may be reset:
    54  //
    55  //     func BenchmarkBigLen(b *testing.B) {
    56  //         big := NewBig()
    57  //         b.ResetTimer()
    58  //         for i := 0; i < b.N; i++ {
    59  //             big.Len()
    60  //         }
    61  //     }
    62  //
    63  // If a benchmark needs to test performance in a parallel setting, it may use
    64  // the RunParallel helper function; such benchmarks are intended to be used with
    65  // the go test -cpu flag:
    66  //
    67  //     func BenchmarkTemplateParallel(b *testing.B) {
    68  //         templ := template.Must(template.New("test").Parse("Hello, {{.}}!"))
    69  //         b.RunParallel(func(pb *testing.PB) {
    70  //             var buf bytes.Buffer
    71  //             for pb.Next() {
    72  //                 buf.Reset()
    73  //                 templ.Execute(&buf, "World")
    74  //             }
    75  //         })
    76  //     }
    77  //
    78  // Examples
    79  //
    80  // The package also runs and verifies example code. Example functions may
    81  // include a concluding line comment that begins with "Output:" and is compared with
    82  // the standard output of the function when the tests are run. (The comparison
    83  // ignores leading and trailing space.) These are examples of an example:
    84  //
    85  //     func ExampleHello() {
    86  //         fmt.Println("hello")
    87  //         // Output: hello
    88  //     }
    89  //
    90  //     func ExampleSalutations() {
    91  //         fmt.Println("hello, and")
    92  //         fmt.Println("goodbye")
    93  //         // Output:
    94  //         // hello, and
    95  //         // goodbye
    96  //     }
    97  //
    98  // The comment prefix "Unordered output:" is like "Output:", but matches any
    99  // line order:
   100  //
   101  //     func ExamplePerm() {
   102  //         for _, value := range Perm(5) {
   103  //             fmt.Println(value)
   104  //         }
   105  //         // Unordered output: 4
   106  //         // 2
   107  //         // 1
   108  //         // 3
   109  //         // 0
   110  //     }
   111  //
   112  // Example functions without output comments are compiled but not executed.
   113  //
   114  // The naming convention to declare examples for the package, a function F, a type T and
   115  // method M on type T are:
   116  //
   117  //     func Example() { ... }
   118  //     func ExampleF() { ... }
   119  //     func ExampleT() { ... }
   120  //     func ExampleT_M() { ... }
   121  //
   122  // Multiple example functions for a package/type/function/method may be provided by
   123  // appending a distinct suffix to the name. The suffix must start with a
   124  // lower-case letter.
   125  //
   126  //     func Example_suffix() { ... }
   127  //     func ExampleF_suffix() { ... }
   128  //     func ExampleT_suffix() { ... }
   129  //     func ExampleT_M_suffix() { ... }
   130  //
   131  // The entire test file is presented as the example when it contains a single
   132  // example function, at least one other function, type, variable, or constant
   133  // declaration, and no test or benchmark functions.
   134  //
   135  // Skipping
   136  //
   137  // Tests or benchmarks may be skipped at run time with a call to
   138  // the Skip method of *T or *B:
   139  //
   140  //     func TestTimeConsuming(t *testing.T) {
   141  //         if testing.Short() {
   142  //             t.Skip("skipping test in short mode.")
   143  //         }
   144  //         ...
   145  //     }
   146  //
   147  // Subtests and Sub-benchmarks
   148  //
   149  // The Run methods of T and B allow defining subtests and sub-benchmarks,
   150  // without having to define separate functions for each. This enables uses
   151  // like table-driven benchmarks and creating hierarchical tests.
   152  // It also provides a way to share common setup and tear-down code:
   153  //
   154  //     func TestFoo(t *testing.T) {
   155  //         // <setup code>
   156  //         t.Run("A=1", func(t *testing.T) { ... })
   157  //         t.Run("A=2", func(t *testing.T) { ... })
   158  //         t.Run("B=1", func(t *testing.T) { ... })
   159  //         // <tear-down code>
   160  //     }
   161  //
   162  // Each subtest and sub-benchmark has a unique name: the combination of the name
   163  // of the top-level test and the sequence of names passed to Run, separated by
   164  // slashes, with an optional trailing sequence number for disambiguation.
   165  //
   166  // The argument to the -run and -bench command-line flags is an unanchored regular
   167  // expression that matches the test's name. For tests with multiple slash-separated
   168  // elements, such as subtests, the argument is itself slash-separated, with
   169  // expressions matching each name element in turn. Because it is unanchored, an
   170  // empty expression matches any string.
   171  // For example, using "matching" to mean "whose name contains":
   172  //
   173  //     go test -run ''      # Run all tests.
   174  //     go test -run Foo     # Run top-level tests matching "Foo", such as "TestFooBar".
   175  //     go test -run Foo/A=  # For top-level tests matching "Foo", run subtests matching "A=".
   176  //     go test -run /A=1    # For all top-level tests, run subtests matching "A=1".
   177  //
   178  // Subtests can also be used to control parallelism. A parent test will only
   179  // complete once all of its subtests complete. In this example, all tests are
   180  // run in parallel with each other, and only with each other, regardless of
   181  // other top-level tests that may be defined:
   182  //
   183  //     func TestGroupedParallel(t *testing.T) {
   184  //         for _, tc := range tests {
   185  //             tc := tc // capture range variable
   186  //             t.Run(tc.Name, func(t *testing.T) {
   187  //                 t.Parallel()
   188  //                 ...
   189  //             })
   190  //         }
   191  //     }
   192  //
   193  // The race detector kills the program if it exceeds 8128 concurrent goroutines,
   194  // so use care when running parallel tests with the -race flag set.
   195  //
   196  // Run does not return until parallel subtests have completed, providing a way
   197  // to clean up after a group of parallel tests:
   198  //
   199  //     func TestTeardownParallel(t *testing.T) {
   200  //         // This Run will not return until the parallel tests finish.
   201  //         t.Run("group", func(t *testing.T) {
   202  //             t.Run("Test1", parallelTest1)
   203  //             t.Run("Test2", parallelTest2)
   204  //             t.Run("Test3", parallelTest3)
   205  //         })
   206  //         // <tear-down code>
   207  //     }
   208  //
   209  // Main
   210  //
   211  // It is sometimes necessary for a test or benchmark program to do extra setup or teardown
   212  // before or after it executes. It is also sometimes necessary to control
   213  // which code runs on the main thread. To support these and other cases,
   214  // if a test file contains a function:
   215  //
   216  //	func TestMain(m *testing.M)
   217  //
   218  // then the generated test will call TestMain(m) instead of running the tests or benchmarks
   219  // directly. TestMain runs in the main goroutine and can do whatever setup
   220  // and teardown is necessary around a call to m.Run. m.Run will return an exit
   221  // code that may be passed to os.Exit. If TestMain returns, the test wrapper
   222  // will pass the result of m.Run to os.Exit itself.
   223  //
   224  // When TestMain is called, flag.Parse has not been run. If TestMain depends on
   225  // command-line flags, including those of the testing package, it should call
   226  // flag.Parse explicitly. Command line flags are always parsed by the time test
   227  // or benchmark functions run.
   228  //
   229  // A simple implementation of TestMain is:
   230  //
   231  //	func TestMain(m *testing.M) {
   232  //		// call flag.Parse() here if TestMain uses flags
   233  //		os.Exit(m.Run())
   234  //	}
   235  //
   236  // TestMain is a low-level primitive and should not be necessary for casual
   237  // testing needs, where ordinary test functions suffice.
   238  package testing
   239  
   240  import (
   241  	"bytes"
   242  	"errors"
   243  	"flag"
   244  	"fmt"
   245  	"internal/race"
   246  	"io"
   247  	"math/rand"
   248  	"os"
   249  	"runtime"
   250  	"runtime/debug"
   251  	"runtime/trace"
   252  	"strconv"
   253  	"strings"
   254  	"sync"
   255  	"sync/atomic"
   256  	"time"
   257  	"unicode"
   258  	"unicode/utf8"
   259  )
   260  
   261  var initRan bool
   262  
   263  // Init registers testing flags. These flags are automatically registered by
   264  // the "go test" command before running test functions, so Init is only needed
   265  // when calling functions such as Benchmark without using "go test".
   266  //
   267  // Init has no effect if it was already called.
   268  func Init() {
   269  	if initRan {
   270  		return
   271  	}
   272  	initRan = true
   273  	// The short flag requests that tests run more quickly, but its functionality
   274  	// is provided by test writers themselves. The testing package is just its
   275  	// home. The all.bash installation script sets it to make installation more
   276  	// efficient, but by default the flag is off so a plain "go test" will do a
   277  	// full test of the package.
   278  	short = flag.Bool("test.short", false, "run smaller test suite to save time")
   279  
   280  	// The failfast flag requests that test execution stop after the first test failure.
   281  	failFast = flag.Bool("test.failfast", false, "do not start new tests after the first test failure")
   282  
   283  	// The directory in which to create profile files and the like. When run from
   284  	// "go test", the binary always runs in the source directory for the package;
   285  	// this flag lets "go test" tell the binary to write the files in the directory where
   286  	// the "go test" command is run.
   287  	outputDir = flag.String("test.outputdir", "", "write profiles to `dir`")
   288  	// Report as tests are run; default is silent for success.
   289  	chatty = flag.Bool("test.v", false, "verbose: print additional output")
   290  	count = flag.Uint("test.count", 1, "run tests and benchmarks `n` times")
   291  	coverProfile = flag.String("test.coverprofile", "", "write a coverage profile to `file`")
   292  	matchList = flag.String("test.list", "", "list tests, examples, and benchmarks matching `regexp` then exit")
   293  	match = flag.String("test.run", "", "run only tests and examples matching `regexp`")
   294  	memProfile = flag.String("test.memprofile", "", "write an allocation profile to `file`")
   295  	memProfileRate = flag.Int("test.memprofilerate", 0, "set memory allocation profiling `rate` (see runtime.MemProfileRate)")
   296  	cpuProfile = flag.String("test.cpuprofile", "", "write a cpu profile to `file`")
   297  	blockProfile = flag.String("test.blockprofile", "", "write a goroutine blocking profile to `file`")
   298  	blockProfileRate = flag.Int("test.blockprofilerate", 1, "set blocking profile `rate` (see runtime.SetBlockProfileRate)")
   299  	mutexProfile = flag.String("test.mutexprofile", "", "write a mutex contention profile to the named file after execution")
   300  	mutexProfileFraction = flag.Int("test.mutexprofilefraction", 1, "if >= 0, calls runtime.SetMutexProfileFraction()")
   301  	panicOnExit0 = flag.Bool("test.paniconexit0", false, "panic on call to os.Exit(0)")
   302  	traceFile = flag.String("test.trace", "", "write an execution trace to `file`")
   303  	timeout = flag.Duration("test.timeout", 0, "panic test binary after duration `d` (default 0, timeout disabled)")
   304  	cpuListStr = flag.String("test.cpu", "", "comma-separated `list` of cpu counts to run each test with")
   305  	parallel = flag.Int("test.parallel", runtime.GOMAXPROCS(0), "run at most `n` tests in parallel")
   306  	testlog = flag.String("test.testlogfile", "", "write test action log to `file` (for use only by cmd/go)")
   307  	shuffle = flag.String("test.shuffle", "off", "randomize the execution order of tests and benchmarks")
   308  
   309  	initBenchmarkFlags()
   310  }
   311  
   312  var (
   313  	// Flags, registered during Init.
   314  	short                *bool
   315  	failFast             *bool
   316  	outputDir            *string
   317  	chatty               *bool
   318  	count                *uint
   319  	coverProfile         *string
   320  	matchList            *string
   321  	match                *string
   322  	memProfile           *string
   323  	memProfileRate       *int
   324  	cpuProfile           *string
   325  	blockProfile         *string
   326  	blockProfileRate     *int
   327  	mutexProfile         *string
   328  	mutexProfileFraction *int
   329  	panicOnExit0         *bool
   330  	traceFile            *string
   331  	timeout              *time.Duration
   332  	cpuListStr           *string
   333  	parallel             *int
   334  	shuffle              *string
   335  	testlog              *string
   336  
   337  	haveExamples bool // are there examples?
   338  
   339  	cpuList     []int
   340  	testlogFile *os.File
   341  
   342  	numFailed uint32 // number of test failures
   343  )
   344  
   345  type chattyPrinter struct {
   346  	w          io.Writer
   347  	lastNameMu sync.Mutex // guards lastName
   348  	lastName   string     // last printed test name in chatty mode
   349  }
   350  
   351  func newChattyPrinter(w io.Writer) *chattyPrinter {
   352  	return &chattyPrinter{w: w}
   353  }
   354  
   355  // Updatef prints a message about the status of the named test to w.
   356  //
   357  // The formatted message must include the test name itself.
   358  func (p *chattyPrinter) Updatef(testName, format string, args ...interface{}) {
   359  	p.lastNameMu.Lock()
   360  	defer p.lastNameMu.Unlock()
   361  
   362  	// Since the message already implies an association with a specific new test,
   363  	// we don't need to check what the old test name was or log an extra CONT line
   364  	// for it. (We're updating it anyway, and the current message already includes
   365  	// the test name.)
   366  	p.lastName = testName
   367  	fmt.Fprintf(p.w, format, args...)
   368  }
   369  
   370  // Printf prints a message, generated by the named test, that does not
   371  // necessarily mention that tests's name itself.
   372  func (p *chattyPrinter) Printf(testName, format string, args ...interface{}) {
   373  	p.lastNameMu.Lock()
   374  	defer p.lastNameMu.Unlock()
   375  
   376  	if p.lastName == "" {
   377  		p.lastName = testName
   378  	} else if p.lastName != testName {
   379  		fmt.Fprintf(p.w, "=== CONT  %s\n", testName)
   380  		p.lastName = testName
   381  	}
   382  
   383  	fmt.Fprintf(p.w, format, args...)
   384  }
   385  
   386  // The maximum number of stack frames to go through when skipping helper functions for
   387  // the purpose of decorating log messages.
   388  const maxStackLen = 50
   389  
   390  // common holds the elements common between T and B and
   391  // captures common methods such as Errorf.
   392  type common struct {
   393  	mu          sync.RWMutex         // guards this group of fields
   394  	output      []byte               // Output generated by test or benchmark.
   395  	w           io.Writer            // For flushToParent.
   396  	ran         bool                 // Test or benchmark (or one of its subtests) was executed.
   397  	failed      bool                 // Test or benchmark has failed.
   398  	skipped     bool                 // Test or benchmark has been skipped.
   399  	done        bool                 // Test is finished and all subtests have completed.
   400  	helperPCs   map[uintptr]struct{} // functions to be skipped when writing file/line info
   401  	helperNames map[string]struct{}  // helperPCs converted to function names
   402  	cleanups    []func()             // optional functions to be called at the end of the test
   403  	cleanupName string               // Name of the cleanup function.
   404  	cleanupPc   []uintptr            // The stack trace at the point where Cleanup was called.
   405  	finished    bool                 // Test function has completed.
   406  
   407  	chatty     *chattyPrinter // A copy of chattyPrinter, if the chatty flag is set.
   408  	bench      bool           // Whether the current test is a benchmark.
   409  	hasSub     int32          // Written atomically.
   410  	raceErrors int            // Number of races detected during test.
   411  	runner     string         // Function name of tRunner running the test.
   412  
   413  	parent   *common
   414  	level    int       // Nesting depth of test or benchmark.
   415  	creator  []uintptr // If level > 0, the stack trace at the point where the parent called t.Run.
   416  	name     string    // Name of test or benchmark.
   417  	start    time.Time // Time test or benchmark started
   418  	duration time.Duration
   419  	barrier  chan bool // To signal parallel subtests they may start.
   420  	signal   chan bool // To signal a test is done.
   421  	sub      []*T      // Queue of subtests to be run in parallel.
   422  
   423  	tempDirMu  sync.Mutex
   424  	tempDir    string
   425  	tempDirErr error
   426  	tempDirSeq int32
   427  }
   428  
   429  // Short reports whether the -test.short flag is set.
   430  func Short() bool {
   431  	if short == nil {
   432  		panic("testing: Short called before Init")
   433  	}
   434  	// Catch code that calls this from TestMain without first calling flag.Parse.
   435  	if !flag.Parsed() {
   436  		panic("testing: Short called before Parse")
   437  	}
   438  
   439  	return *short
   440  }
   441  
   442  // CoverMode reports what the test coverage mode is set to. The
   443  // values are "set", "count", or "atomic". The return value will be
   444  // empty if test coverage is not enabled.
   445  func CoverMode() string {
   446  	return cover.Mode
   447  }
   448  
   449  // Verbose reports whether the -test.v flag is set.
   450  func Verbose() bool {
   451  	// Same as in Short.
   452  	if chatty == nil {
   453  		panic("testing: Verbose called before Init")
   454  	}
   455  	if !flag.Parsed() {
   456  		panic("testing: Verbose called before Parse")
   457  	}
   458  	return *chatty
   459  }
   460  
   461  // frameSkip searches, starting after skip frames, for the first caller frame
   462  // in a function not marked as a helper and returns that frame.
   463  // The search stops if it finds a tRunner function that
   464  // was the entry point into the test and the test is not a subtest.
   465  // This function must be called with c.mu held.
   466  func (c *common) frameSkip(skip int) runtime.Frame {
   467  	// If the search continues into the parent test, we'll have to hold
   468  	// its mu temporarily. If we then return, we need to unlock it.
   469  	shouldUnlock := false
   470  	defer func() {
   471  		if shouldUnlock {
   472  			c.mu.Unlock()
   473  		}
   474  	}()
   475  	var pc [maxStackLen]uintptr
   476  	// Skip two extra frames to account for this function
   477  	// and runtime.Callers itself.
   478  	n := runtime.Callers(skip+2, pc[:])
   479  	if n == 0 {
   480  		panic("testing: zero callers found")
   481  	}
   482  	frames := runtime.CallersFrames(pc[:n])
   483  	var firstFrame, prevFrame, frame runtime.Frame
   484  	for more := true; more; prevFrame = frame {
   485  		frame, more = frames.Next()
   486  		if frame.Function == c.cleanupName {
   487  			frames = runtime.CallersFrames(c.cleanupPc)
   488  			continue
   489  		}
   490  		if firstFrame.PC == 0 {
   491  			firstFrame = frame
   492  		}
   493  		if frame.Function == c.runner {
   494  			// We've gone up all the way to the tRunner calling
   495  			// the test function (so the user must have
   496  			// called tb.Helper from inside that test function).
   497  			// If this is a top-level test, only skip up to the test function itself.
   498  			// If we're in a subtest, continue searching in the parent test,
   499  			// starting from the point of the call to Run which created this subtest.
   500  			if c.level > 1 {
   501  				frames = runtime.CallersFrames(c.creator)
   502  				parent := c.parent
   503  				// We're no longer looking at the current c after this point,
   504  				// so we should unlock its mu, unless it's the original receiver,
   505  				// in which case our caller doesn't expect us to do that.
   506  				if shouldUnlock {
   507  					c.mu.Unlock()
   508  				}
   509  				c = parent
   510  				// Remember to unlock c.mu when we no longer need it, either
   511  				// because we went up another nesting level, or because we
   512  				// returned.
   513  				shouldUnlock = true
   514  				c.mu.Lock()
   515  				continue
   516  			}
   517  			return prevFrame
   518  		}
   519  		// If more helper PCs have been added since we last did the conversion
   520  		if c.helperNames == nil {
   521  			c.helperNames = make(map[string]struct{})
   522  			for pc := range c.helperPCs {
   523  				c.helperNames[pcToName(pc)] = struct{}{}
   524  			}
   525  		}
   526  		if _, ok := c.helperNames[frame.Function]; !ok {
   527  			// Found a frame that wasn't inside a helper function.
   528  			return frame
   529  		}
   530  	}
   531  	return firstFrame
   532  }
   533  
   534  // decorate prefixes the string with the file and line of the call site
   535  // and inserts the final newline if needed and indentation spaces for formatting.
   536  // This function must be called with c.mu held.
   537  func (c *common) decorate(s string, skip int) string {
   538  	frame := c.frameSkip(skip)
   539  	file := frame.File
   540  	line := frame.Line
   541  	if file != "" {
   542  		// Truncate file name at last file name separator.
   543  		if index := strings.LastIndex(file, "/"); index >= 0 {
   544  			file = file[index+1:]
   545  		} else if index = strings.LastIndex(file, "\\"); index >= 0 {
   546  			file = file[index+1:]
   547  		}
   548  	} else {
   549  		file = "???"
   550  	}
   551  	if line == 0 {
   552  		line = 1
   553  	}
   554  	buf := new(strings.Builder)
   555  	// Every line is indented at least 4 spaces.
   556  	buf.WriteString("    ")
   557  	fmt.Fprintf(buf, "%s:%d: ", file, line)
   558  	lines := strings.Split(s, "\n")
   559  	if l := len(lines); l > 1 && lines[l-1] == "" {
   560  		lines = lines[:l-1]
   561  	}
   562  	for i, line := range lines {
   563  		if i > 0 {
   564  			// Second and subsequent lines are indented an additional 4 spaces.
   565  			buf.WriteString("\n        ")
   566  		}
   567  		buf.WriteString(line)
   568  	}
   569  	buf.WriteByte('\n')
   570  	return buf.String()
   571  }
   572  
   573  // flushToParent writes c.output to the parent after first writing the header
   574  // with the given format and arguments.
   575  func (c *common) flushToParent(testName, format string, args ...interface{}) {
   576  	p := c.parent
   577  	p.mu.Lock()
   578  	defer p.mu.Unlock()
   579  
   580  	c.mu.Lock()
   581  	defer c.mu.Unlock()
   582  
   583  	if len(c.output) > 0 {
   584  		format += "%s"
   585  		args = append(args[:len(args):len(args)], c.output)
   586  		c.output = c.output[:0] // but why?
   587  	}
   588  
   589  	if c.chatty != nil && p.w == c.chatty.w {
   590  		// We're flushing to the actual output, so track that this output is
   591  		// associated with a specific test (and, specifically, that the next output
   592  		// is *not* associated with that test).
   593  		//
   594  		// Moreover, if c.output is non-empty it is important that this write be
   595  		// atomic with respect to the output of other tests, so that we don't end up
   596  		// with confusing '=== CONT' lines in the middle of our '--- PASS' block.
   597  		// Neither humans nor cmd/test2json can parse those easily.
   598  		// (See https://golang.org/issue/40771.)
   599  		c.chatty.Updatef(testName, format, args...)
   600  	} else {
   601  		// We're flushing to the output buffer of the parent test, which will
   602  		// itself follow a test-name header when it is finally flushed to stdout.
   603  		fmt.Fprintf(p.w, format, args...)
   604  	}
   605  }
   606  
   607  type indenter struct {
   608  	c *common
   609  }
   610  
   611  func (w indenter) Write(b []byte) (n int, err error) {
   612  	n = len(b)
   613  	for len(b) > 0 {
   614  		end := bytes.IndexByte(b, '\n')
   615  		if end == -1 {
   616  			end = len(b)
   617  		} else {
   618  			end++
   619  		}
   620  		// An indent of 4 spaces will neatly align the dashes with the status
   621  		// indicator of the parent.
   622  		const indent = "    "
   623  		w.c.output = append(w.c.output, indent...)
   624  		w.c.output = append(w.c.output, b[:end]...)
   625  		b = b[end:]
   626  	}
   627  	return
   628  }
   629  
   630  // fmtDuration returns a string representing d in the form "87.00s".
   631  func fmtDuration(d time.Duration) string {
   632  	return fmt.Sprintf("%.2fs", d.Seconds())
   633  }
   634  
   635  // TB is the interface common to T and B.
   636  type TB interface {
   637  	Cleanup(func())
   638  	Error(args ...interface{})
   639  	Errorf(format string, args ...interface{})
   640  	Fail()
   641  	FailNow()
   642  	Failed() bool
   643  	Fatal(args ...interface{})
   644  	Fatalf(format string, args ...interface{})
   645  	Helper()
   646  	Log(args ...interface{})
   647  	Logf(format string, args ...interface{})
   648  	Name() string
   649  	Setenv(key, value string)
   650  	Skip(args ...interface{})
   651  	SkipNow()
   652  	Skipf(format string, args ...interface{})
   653  	Skipped() bool
   654  	TempDir() string
   655  
   656  	// A private method to prevent users implementing the
   657  	// interface and so future additions to it will not
   658  	// violate Go 1 compatibility.
   659  	private()
   660  }
   661  
   662  var _ TB = (*T)(nil)
   663  var _ TB = (*B)(nil)
   664  
   665  // T is a type passed to Test functions to manage test state and support formatted test logs.
   666  //
   667  // A test ends when its Test function returns or calls any of the methods
   668  // FailNow, Fatal, Fatalf, SkipNow, Skip, or Skipf. Those methods, as well as
   669  // the Parallel method, must be called only from the goroutine running the
   670  // Test function.
   671  //
   672  // The other reporting methods, such as the variations of Log and Error,
   673  // may be called simultaneously from multiple goroutines.
   674  type T struct {
   675  	common
   676  	isParallel bool
   677  	isEnvSet   bool
   678  	context    *testContext // For running tests and subtests.
   679  }
   680  
   681  func (c *common) private() {}
   682  
   683  // Name returns the name of the running (sub-) test or benchmark.
   684  //
   685  // The name will include the name of the test along with the names of
   686  // any nested sub-tests. If two sibling sub-tests have the same name,
   687  // Name will append a suffix to guarantee the returned name is unique.
   688  func (c *common) Name() string {
   689  	return c.name
   690  }
   691  
   692  func (c *common) setRan() {
   693  	if c.parent != nil {
   694  		c.parent.setRan()
   695  	}
   696  	c.mu.Lock()
   697  	defer c.mu.Unlock()
   698  	c.ran = true
   699  }
   700  
   701  // Fail marks the function as having failed but continues execution.
   702  func (c *common) Fail() {
   703  	if c.parent != nil {
   704  		c.parent.Fail()
   705  	}
   706  	c.mu.Lock()
   707  	defer c.mu.Unlock()
   708  	// c.done needs to be locked to synchronize checks to c.done in parent tests.
   709  	if c.done {
   710  		panic("Fail in goroutine after " + c.name + " has completed")
   711  	}
   712  	c.failed = true
   713  }
   714  
   715  // Failed reports whether the function has failed.
   716  func (c *common) Failed() bool {
   717  	c.mu.RLock()
   718  	failed := c.failed
   719  	c.mu.RUnlock()
   720  	return failed || c.raceErrors+race.Errors() > 0
   721  }
   722  
   723  // FailNow marks the function as having failed and stops its execution
   724  // by calling runtime.Goexit (which then runs all deferred calls in the
   725  // current goroutine).
   726  // Execution will continue at the next test or benchmark.
   727  // FailNow must be called from the goroutine running the
   728  // test or benchmark function, not from other goroutines
   729  // created during the test. Calling FailNow does not stop
   730  // those other goroutines.
   731  func (c *common) FailNow() {
   732  	c.Fail()
   733  
   734  	// Calling runtime.Goexit will exit the goroutine, which
   735  	// will run the deferred functions in this goroutine,
   736  	// which will eventually run the deferred lines in tRunner,
   737  	// which will signal to the test loop that this test is done.
   738  	//
   739  	// A previous version of this code said:
   740  	//
   741  	//	c.duration = ...
   742  	//	c.signal <- c.self
   743  	//	runtime.Goexit()
   744  	//
   745  	// This previous version duplicated code (those lines are in
   746  	// tRunner no matter what), but worse the goroutine teardown
   747  	// implicit in runtime.Goexit was not guaranteed to complete
   748  	// before the test exited. If a test deferred an important cleanup
   749  	// function (like removing temporary files), there was no guarantee
   750  	// it would run on a test failure. Because we send on c.signal during
   751  	// a top-of-stack deferred function now, we know that the send
   752  	// only happens after any other stacked defers have completed.
   753  	c.mu.Lock()
   754  	c.finished = true
   755  	c.mu.Unlock()
   756  	runtime.Goexit()
   757  }
   758  
   759  // log generates the output. It's always at the same stack depth.
   760  func (c *common) log(s string) {
   761  	c.logDepth(s, 3) // logDepth + log + public function
   762  }
   763  
   764  // logDepth generates the output at an arbitrary stack depth.
   765  func (c *common) logDepth(s string, depth int) {
   766  	c.mu.Lock()
   767  	defer c.mu.Unlock()
   768  	if c.done {
   769  		// This test has already finished. Try and log this message
   770  		// with our parent. If we don't have a parent, panic.
   771  		for parent := c.parent; parent != nil; parent = parent.parent {
   772  			parent.mu.Lock()
   773  			defer parent.mu.Unlock()
   774  			if !parent.done {
   775  				parent.output = append(parent.output, parent.decorate(s, depth+1)...)
   776  				return
   777  			}
   778  		}
   779  		panic("Log in goroutine after " + c.name + " has completed: " + s)
   780  	} else {
   781  		if c.chatty != nil {
   782  			if c.bench {
   783  				// Benchmarks don't print === CONT, so we should skip the test
   784  				// printer and just print straight to stdout.
   785  				fmt.Print(c.decorate(s, depth+1))
   786  			} else {
   787  				c.chatty.Printf(c.name, "%s", c.decorate(s, depth+1))
   788  			}
   789  
   790  			return
   791  		}
   792  		c.output = append(c.output, c.decorate(s, depth+1)...)
   793  	}
   794  }
   795  
   796  // Log formats its arguments using default formatting, analogous to Println,
   797  // and records the text in the error log. For tests, the text will be printed only if
   798  // the test fails or the -test.v flag is set. For benchmarks, the text is always
   799  // printed to avoid having performance depend on the value of the -test.v flag.
   800  func (c *common) Log(args ...interface{}) { c.log(fmt.Sprintln(args...)) }
   801  
   802  // Logf formats its arguments according to the format, analogous to Printf, and
   803  // records the text in the error log. A final newline is added if not provided. For
   804  // tests, the text will be printed only if the test fails or the -test.v flag is
   805  // set. For benchmarks, the text is always printed to avoid having performance
   806  // depend on the value of the -test.v flag.
   807  func (c *common) Logf(format string, args ...interface{}) { c.log(fmt.Sprintf(format, args...)) }
   808  
   809  // Error is equivalent to Log followed by Fail.
   810  func (c *common) Error(args ...interface{}) {
   811  	c.log(fmt.Sprintln(args...))
   812  	c.Fail()
   813  }
   814  
   815  // Errorf is equivalent to Logf followed by Fail.
   816  func (c *common) Errorf(format string, args ...interface{}) {
   817  	c.log(fmt.Sprintf(format, args...))
   818  	c.Fail()
   819  }
   820  
   821  // Fatal is equivalent to Log followed by FailNow.
   822  func (c *common) Fatal(args ...interface{}) {
   823  	c.log(fmt.Sprintln(args...))
   824  	c.FailNow()
   825  }
   826  
   827  // Fatalf is equivalent to Logf followed by FailNow.
   828  func (c *common) Fatalf(format string, args ...interface{}) {
   829  	c.log(fmt.Sprintf(format, args...))
   830  	c.FailNow()
   831  }
   832  
   833  // Skip is equivalent to Log followed by SkipNow.
   834  func (c *common) Skip(args ...interface{}) {
   835  	c.log(fmt.Sprintln(args...))
   836  	c.SkipNow()
   837  }
   838  
   839  // Skipf is equivalent to Logf followed by SkipNow.
   840  func (c *common) Skipf(format string, args ...interface{}) {
   841  	c.log(fmt.Sprintf(format, args...))
   842  	c.SkipNow()
   843  }
   844  
   845  // SkipNow marks the test as having been skipped and stops its execution
   846  // by calling runtime.Goexit.
   847  // If a test fails (see Error, Errorf, Fail) and is then skipped,
   848  // it is still considered to have failed.
   849  // Execution will continue at the next test or benchmark. See also FailNow.
   850  // SkipNow must be called from the goroutine running the test, not from
   851  // other goroutines created during the test. Calling SkipNow does not stop
   852  // those other goroutines.
   853  func (c *common) SkipNow() {
   854  	c.mu.Lock()
   855  	c.skipped = true
   856  	c.finished = true
   857  	c.mu.Unlock()
   858  	runtime.Goexit()
   859  }
   860  
   861  // Skipped reports whether the test was skipped.
   862  func (c *common) Skipped() bool {
   863  	c.mu.RLock()
   864  	defer c.mu.RUnlock()
   865  	return c.skipped
   866  }
   867  
   868  // Helper marks the calling function as a test helper function.
   869  // When printing file and line information, that function will be skipped.
   870  // Helper may be called simultaneously from multiple goroutines.
   871  func (c *common) Helper() {
   872  	c.mu.Lock()
   873  	defer c.mu.Unlock()
   874  	if c.helperPCs == nil {
   875  		c.helperPCs = make(map[uintptr]struct{})
   876  	}
   877  	// repeating code from callerName here to save walking a stack frame
   878  	var pc [1]uintptr
   879  	n := runtime.Callers(2, pc[:]) // skip runtime.Callers + Helper
   880  	if n == 0 {
   881  		panic("testing: zero callers found")
   882  	}
   883  	if _, found := c.helperPCs[pc[0]]; !found {
   884  		c.helperPCs[pc[0]] = struct{}{}
   885  		c.helperNames = nil // map will be recreated next time it is needed
   886  	}
   887  }
   888  
   889  // Cleanup registers a function to be called when the test (or subtest) and all its
   890  // subtests complete. Cleanup functions will be called in last added,
   891  // first called order.
   892  func (c *common) Cleanup(f func()) {
   893  	var pc [maxStackLen]uintptr
   894  	// Skip two extra frames to account for this function and runtime.Callers itself.
   895  	n := runtime.Callers(2, pc[:])
   896  	cleanupPc := pc[:n]
   897  
   898  	fn := func() {
   899  		defer func() {
   900  			c.mu.Lock()
   901  			defer c.mu.Unlock()
   902  			c.cleanupName = ""
   903  			c.cleanupPc = nil
   904  		}()
   905  
   906  		name := callerName(0)
   907  		c.mu.Lock()
   908  		c.cleanupName = name
   909  		c.cleanupPc = cleanupPc
   910  		c.mu.Unlock()
   911  
   912  		f()
   913  	}
   914  
   915  	c.mu.Lock()
   916  	defer c.mu.Unlock()
   917  	c.cleanups = append(c.cleanups, fn)
   918  }
   919  
   920  // TempDir returns a temporary directory for the test to use.
   921  // The directory is automatically removed by Cleanup when the test and
   922  // all its subtests complete.
   923  // Each subsequent call to t.TempDir returns a unique directory;
   924  // if the directory creation fails, TempDir terminates the test by calling Fatal.
   925  func (c *common) TempDir() string {
   926  	// Use a single parent directory for all the temporary directories
   927  	// created by a test, each numbered sequentially.
   928  	c.tempDirMu.Lock()
   929  	var nonExistent bool
   930  	if c.tempDir == "" { // Usually the case with js/wasm
   931  		nonExistent = true
   932  	} else {
   933  		_, err := os.Stat(c.tempDir)
   934  		nonExistent = os.IsNotExist(err)
   935  		if err != nil && !nonExistent {
   936  			c.Fatalf("TempDir: %v", err)
   937  		}
   938  	}
   939  
   940  	if nonExistent {
   941  		c.Helper()
   942  
   943  		// Drop unusual characters (such as path separators or
   944  		// characters interacting with globs) from the directory name to
   945  		// avoid surprising os.MkdirTemp behavior.
   946  		mapper := func(r rune) rune {
   947  			if r < utf8.RuneSelf {
   948  				const allowed = "!#$%&()+,-.=@^_{}~ "
   949  				if '0' <= r && r <= '9' ||
   950  					'a' <= r && r <= 'z' ||
   951  					'A' <= r && r <= 'Z' {
   952  					return r
   953  				}
   954  				if strings.ContainsRune(allowed, r) {
   955  					return r
   956  				}
   957  			} else if unicode.IsLetter(r) || unicode.IsNumber(r) {
   958  				return r
   959  			}
   960  			return -1
   961  		}
   962  		pattern := strings.Map(mapper, c.Name())
   963  		c.tempDir, c.tempDirErr = os.MkdirTemp("", pattern)
   964  		if c.tempDirErr == nil {
   965  			c.Cleanup(func() {
   966  				if err := os.RemoveAll(c.tempDir); err != nil {
   967  					c.Errorf("TempDir RemoveAll cleanup: %v", err)
   968  				}
   969  			})
   970  		}
   971  	}
   972  	c.tempDirMu.Unlock()
   973  
   974  	if c.tempDirErr != nil {
   975  		c.Fatalf("TempDir: %v", c.tempDirErr)
   976  	}
   977  	seq := atomic.AddInt32(&c.tempDirSeq, 1)
   978  	dir := fmt.Sprintf("%s%c%03d", c.tempDir, os.PathSeparator, seq)
   979  	if err := os.Mkdir(dir, 0777); err != nil {
   980  		c.Fatalf("TempDir: %v", err)
   981  	}
   982  	return dir
   983  }
   984  
   985  // Setenv calls os.Setenv(key, value) and uses Cleanup to
   986  // restore the environment variable to its original value
   987  // after the test.
   988  //
   989  // This cannot be used in parallel tests.
   990  func (c *common) Setenv(key, value string) {
   991  	prevValue, ok := os.LookupEnv(key)
   992  
   993  	if err := os.Setenv(key, value); err != nil {
   994  		c.Fatalf("cannot set environment variable: %v", err)
   995  	}
   996  
   997  	if ok {
   998  		c.Cleanup(func() {
   999  			os.Setenv(key, prevValue)
  1000  		})
  1001  	} else {
  1002  		c.Cleanup(func() {
  1003  			os.Unsetenv(key)
  1004  		})
  1005  	}
  1006  }
  1007  
  1008  // panicHanding is an argument to runCleanup.
  1009  type panicHandling int
  1010  
  1011  const (
  1012  	normalPanic panicHandling = iota
  1013  	recoverAndReturnPanic
  1014  )
  1015  
  1016  // runCleanup is called at the end of the test.
  1017  // If catchPanic is true, this will catch panics, and return the recovered
  1018  // value if any.
  1019  func (c *common) runCleanup(ph panicHandling) (panicVal interface{}) {
  1020  	if ph == recoverAndReturnPanic {
  1021  		defer func() {
  1022  			panicVal = recover()
  1023  		}()
  1024  	}
  1025  
  1026  	// Make sure that if a cleanup function panics,
  1027  	// we still run the remaining cleanup functions.
  1028  	defer func() {
  1029  		c.mu.Lock()
  1030  		recur := len(c.cleanups) > 0
  1031  		c.mu.Unlock()
  1032  		if recur {
  1033  			c.runCleanup(normalPanic)
  1034  		}
  1035  	}()
  1036  
  1037  	for {
  1038  		var cleanup func()
  1039  		c.mu.Lock()
  1040  		if len(c.cleanups) > 0 {
  1041  			last := len(c.cleanups) - 1
  1042  			cleanup = c.cleanups[last]
  1043  			c.cleanups = c.cleanups[:last]
  1044  		}
  1045  		c.mu.Unlock()
  1046  		if cleanup == nil {
  1047  			return nil
  1048  		}
  1049  		cleanup()
  1050  	}
  1051  }
  1052  
  1053  // callerName gives the function name (qualified with a package path)
  1054  // for the caller after skip frames (where 0 means the current function).
  1055  func callerName(skip int) string {
  1056  	var pc [1]uintptr
  1057  	n := runtime.Callers(skip+2, pc[:]) // skip + runtime.Callers + callerName
  1058  	if n == 0 {
  1059  		panic("testing: zero callers found")
  1060  	}
  1061  	return pcToName(pc[0])
  1062  }
  1063  
  1064  func pcToName(pc uintptr) string {
  1065  	pcs := []uintptr{pc}
  1066  	frames := runtime.CallersFrames(pcs)
  1067  	frame, _ := frames.Next()
  1068  	return frame.Function
  1069  }
  1070  
  1071  // Parallel signals that this test is to be run in parallel with (and only with)
  1072  // other parallel tests. When a test is run multiple times due to use of
  1073  // -test.count or -test.cpu, multiple instances of a single test never run in
  1074  // parallel with each other.
  1075  func (t *T) Parallel() {
  1076  	if t.isParallel {
  1077  		panic("testing: t.Parallel called multiple times")
  1078  	}
  1079  	if t.isEnvSet {
  1080  		panic("testing: t.Parallel called after t.Setenv; cannot set environment variables in parallel tests")
  1081  	}
  1082  	t.isParallel = true
  1083  
  1084  	// We don't want to include the time we spend waiting for serial tests
  1085  	// in the test duration. Record the elapsed time thus far and reset the
  1086  	// timer afterwards.
  1087  	t.duration += time.Since(t.start)
  1088  
  1089  	// Add to the list of tests to be released by the parent.
  1090  	t.parent.sub = append(t.parent.sub, t)
  1091  	t.raceErrors += race.Errors()
  1092  
  1093  	if t.chatty != nil {
  1094  		// Unfortunately, even though PAUSE indicates that the named test is *no
  1095  		// longer* running, cmd/test2json interprets it as changing the active test
  1096  		// for the purpose of log parsing. We could fix cmd/test2json, but that
  1097  		// won't fix existing deployments of third-party tools that already shell
  1098  		// out to older builds of cmd/test2json — so merely fixing cmd/test2json
  1099  		// isn't enough for now.
  1100  		t.chatty.Updatef(t.name, "=== PAUSE %s\n", t.name)
  1101  	}
  1102  
  1103  	t.signal <- true   // Release calling test.
  1104  	<-t.parent.barrier // Wait for the parent test to complete.
  1105  	t.context.waitParallel()
  1106  
  1107  	if t.chatty != nil {
  1108  		t.chatty.Updatef(t.name, "=== CONT  %s\n", t.name)
  1109  	}
  1110  
  1111  	t.start = time.Now()
  1112  	t.raceErrors += -race.Errors()
  1113  }
  1114  
  1115  // Setenv calls os.Setenv(key, value) and uses Cleanup to
  1116  // restore the environment variable to its original value
  1117  // after the test.
  1118  //
  1119  // This cannot be used in parallel tests.
  1120  func (t *T) Setenv(key, value string) {
  1121  	if t.isParallel {
  1122  		panic("testing: t.Setenv called after t.Parallel; cannot set environment variables in parallel tests")
  1123  	}
  1124  
  1125  	t.isEnvSet = true
  1126  
  1127  	t.common.Setenv(key, value)
  1128  }
  1129  
  1130  // InternalTest is an internal type but exported because it is cross-package;
  1131  // it is part of the implementation of the "go test" command.
  1132  type InternalTest struct {
  1133  	Name string
  1134  	F    func(*T)
  1135  }
  1136  
  1137  var errNilPanicOrGoexit = errors.New("test executed panic(nil) or runtime.Goexit")
  1138  
  1139  func tRunner(t *T, fn func(t *T)) {
  1140  	t.runner = callerName(0)
  1141  
  1142  	// When this goroutine is done, either because fn(t)
  1143  	// returned normally or because a test failure triggered
  1144  	// a call to runtime.Goexit, record the duration and send
  1145  	// a signal saying that the test is done.
  1146  	defer func() {
  1147  		if t.Failed() {
  1148  			atomic.AddUint32(&numFailed, 1)
  1149  		}
  1150  
  1151  		if t.raceErrors+race.Errors() > 0 {
  1152  			t.Errorf("race detected during execution of test")
  1153  		}
  1154  
  1155  		// If the test panicked, print any test output before dying.
  1156  		err := recover()
  1157  		signal := true
  1158  
  1159  		t.mu.RLock()
  1160  		finished := t.finished
  1161  		t.mu.RUnlock()
  1162  		if !finished && err == nil {
  1163  			err = errNilPanicOrGoexit
  1164  			for p := t.parent; p != nil; p = p.parent {
  1165  				p.mu.RLock()
  1166  				finished = p.finished
  1167  				p.mu.RUnlock()
  1168  				if finished {
  1169  					t.Errorf("%v: subtest may have called FailNow on a parent test", err)
  1170  					err = nil
  1171  					signal = false
  1172  					break
  1173  				}
  1174  			}
  1175  		}
  1176  		// Use a deferred call to ensure that we report that the test is
  1177  		// complete even if a cleanup function calls t.FailNow. See issue 41355.
  1178  		didPanic := false
  1179  		defer func() {
  1180  			if didPanic {
  1181  				return
  1182  			}
  1183  			if err != nil {
  1184  				panic(err)
  1185  			}
  1186  			// Only report that the test is complete if it doesn't panic,
  1187  			// as otherwise the test binary can exit before the panic is
  1188  			// reported to the user. See issue 41479.
  1189  			t.signal <- signal
  1190  		}()
  1191  
  1192  		doPanic := func(err interface{}) {
  1193  			t.Fail()
  1194  			if r := t.runCleanup(recoverAndReturnPanic); r != nil {
  1195  				t.Logf("cleanup panicked with %v", r)
  1196  			}
  1197  			// Flush the output log up to the root before dying.
  1198  			for root := &t.common; root.parent != nil; root = root.parent {
  1199  				root.mu.Lock()
  1200  				root.duration += time.Since(root.start)
  1201  				d := root.duration
  1202  				root.mu.Unlock()
  1203  				root.flushToParent(root.name, "--- FAIL: %s (%s)\n", root.name, fmtDuration(d))
  1204  				if r := root.parent.runCleanup(recoverAndReturnPanic); r != nil {
  1205  					fmt.Fprintf(root.parent.w, "cleanup panicked with %v", r)
  1206  				}
  1207  			}
  1208  			didPanic = true
  1209  			panic(err)
  1210  		}
  1211  		if err != nil {
  1212  			doPanic(err)
  1213  		}
  1214  
  1215  		t.duration += time.Since(t.start)
  1216  
  1217  		if len(t.sub) > 0 {
  1218  			// Run parallel subtests.
  1219  			// Decrease the running count for this test.
  1220  			t.context.release()
  1221  			// Release the parallel subtests.
  1222  			close(t.barrier)
  1223  			// Wait for subtests to complete.
  1224  			for _, sub := range t.sub {
  1225  				<-sub.signal
  1226  			}
  1227  			cleanupStart := time.Now()
  1228  			err := t.runCleanup(recoverAndReturnPanic)
  1229  			t.duration += time.Since(cleanupStart)
  1230  			if err != nil {
  1231  				doPanic(err)
  1232  			}
  1233  			if !t.isParallel {
  1234  				// Reacquire the count for sequential tests. See comment in Run.
  1235  				t.context.waitParallel()
  1236  			}
  1237  		} else if t.isParallel {
  1238  			// Only release the count for this test if it was run as a parallel
  1239  			// test. See comment in Run method.
  1240  			t.context.release()
  1241  		}
  1242  		t.report() // Report after all subtests have finished.
  1243  
  1244  		// Do not lock t.done to allow race detector to detect race in case
  1245  		// the user does not appropriately synchronizes a goroutine.
  1246  		t.done = true
  1247  		if t.parent != nil && atomic.LoadInt32(&t.hasSub) == 0 {
  1248  			t.setRan()
  1249  		}
  1250  	}()
  1251  	defer func() {
  1252  		if len(t.sub) == 0 {
  1253  			t.runCleanup(normalPanic)
  1254  		}
  1255  	}()
  1256  
  1257  	t.start = time.Now()
  1258  	t.raceErrors = -race.Errors()
  1259  	fn(t)
  1260  
  1261  	// code beyond here will not be executed when FailNow is invoked
  1262  	t.mu.Lock()
  1263  	t.finished = true
  1264  	t.mu.Unlock()
  1265  }
  1266  
  1267  // Run runs f as a subtest of t called name. It runs f in a separate goroutine
  1268  // and blocks until f returns or calls t.Parallel to become a parallel test.
  1269  // Run reports whether f succeeded (or at least did not fail before calling t.Parallel).
  1270  //
  1271  // Run may be called simultaneously from multiple goroutines, but all such calls
  1272  // must return before the outer test function for t returns.
  1273  func (t *T) Run(name string, f func(t *T)) bool {
  1274  	atomic.StoreInt32(&t.hasSub, 1)
  1275  	testName, ok, _ := t.context.match.fullName(&t.common, name)
  1276  	if !ok || shouldFailFast() {
  1277  		return true
  1278  	}
  1279  	// Record the stack trace at the point of this call so that if the subtest
  1280  	// function - which runs in a separate stack - is marked as a helper, we can
  1281  	// continue walking the stack into the parent test.
  1282  	var pc [maxStackLen]uintptr
  1283  	n := runtime.Callers(2, pc[:])
  1284  	t = &T{
  1285  		common: common{
  1286  			barrier: make(chan bool),
  1287  			signal:  make(chan bool, 1),
  1288  			name:    testName,
  1289  			parent:  &t.common,
  1290  			level:   t.level + 1,
  1291  			creator: pc[:n],
  1292  			chatty:  t.chatty,
  1293  		},
  1294  		context: t.context,
  1295  	}
  1296  	t.w = indenter{&t.common}
  1297  
  1298  	if t.chatty != nil {
  1299  		t.chatty.Updatef(t.name, "=== RUN   %s\n", t.name)
  1300  	}
  1301  	// Instead of reducing the running count of this test before calling the
  1302  	// tRunner and increasing it afterwards, we rely on tRunner keeping the
  1303  	// count correct. This ensures that a sequence of sequential tests runs
  1304  	// without being preempted, even when their parent is a parallel test. This
  1305  	// may especially reduce surprises if *parallel == 1.
  1306  	go tRunner(t, f)
  1307  	if !<-t.signal {
  1308  		// At this point, it is likely that FailNow was called on one of the
  1309  		// parent tests by one of the subtests. Continue aborting up the chain.
  1310  		runtime.Goexit()
  1311  	}
  1312  	return !t.failed
  1313  }
  1314  
  1315  // Deadline reports the time at which the test binary will have
  1316  // exceeded the timeout specified by the -timeout flag.
  1317  //
  1318  // The ok result is false if the -timeout flag indicates “no timeout” (0).
  1319  func (t *T) Deadline() (deadline time.Time, ok bool) {
  1320  	deadline = t.context.deadline
  1321  	return deadline, !deadline.IsZero()
  1322  }
  1323  
  1324  // testContext holds all fields that are common to all tests. This includes
  1325  // synchronization primitives to run at most *parallel tests.
  1326  type testContext struct {
  1327  	match    *matcher
  1328  	deadline time.Time
  1329  
  1330  	mu sync.Mutex
  1331  
  1332  	// Channel used to signal tests that are ready to be run in parallel.
  1333  	startParallel chan bool
  1334  
  1335  	// running is the number of tests currently running in parallel.
  1336  	// This does not include tests that are waiting for subtests to complete.
  1337  	running int
  1338  
  1339  	// numWaiting is the number tests waiting to be run in parallel.
  1340  	numWaiting int
  1341  
  1342  	// maxParallel is a copy of the parallel flag.
  1343  	maxParallel int
  1344  }
  1345  
  1346  func newTestContext(maxParallel int, m *matcher) *testContext {
  1347  	return &testContext{
  1348  		match:         m,
  1349  		startParallel: make(chan bool),
  1350  		maxParallel:   maxParallel,
  1351  		running:       1, // Set the count to 1 for the main (sequential) test.
  1352  	}
  1353  }
  1354  
  1355  func (c *testContext) waitParallel() {
  1356  	c.mu.Lock()
  1357  	if c.running < c.maxParallel {
  1358  		c.running++
  1359  		c.mu.Unlock()
  1360  		return
  1361  	}
  1362  	c.numWaiting++
  1363  	c.mu.Unlock()
  1364  	<-c.startParallel
  1365  }
  1366  
  1367  func (c *testContext) release() {
  1368  	c.mu.Lock()
  1369  	if c.numWaiting == 0 {
  1370  		c.running--
  1371  		c.mu.Unlock()
  1372  		return
  1373  	}
  1374  	c.numWaiting--
  1375  	c.mu.Unlock()
  1376  	c.startParallel <- true // Pick a waiting test to be run.
  1377  }
  1378  
  1379  // No one should be using func Main anymore.
  1380  // See the doc comment on func Main and use MainStart instead.
  1381  var errMain = errors.New("testing: unexpected use of func Main")
  1382  
  1383  type matchStringOnly func(pat, str string) (bool, error)
  1384  
  1385  func (f matchStringOnly) MatchString(pat, str string) (bool, error)   { return f(pat, str) }
  1386  func (f matchStringOnly) StartCPUProfile(w io.Writer) error           { return errMain }
  1387  func (f matchStringOnly) StopCPUProfile()                             {}
  1388  func (f matchStringOnly) WriteProfileTo(string, io.Writer, int) error { return errMain }
  1389  func (f matchStringOnly) ImportPath() string                          { return "" }
  1390  func (f matchStringOnly) StartTestLog(io.Writer)                      {}
  1391  func (f matchStringOnly) StopTestLog() error                          { return errMain }
  1392  func (f matchStringOnly) SetPanicOnExit0(bool)                        {}
  1393  
  1394  // Main is an internal function, part of the implementation of the "go test" command.
  1395  // It was exported because it is cross-package and predates "internal" packages.
  1396  // It is no longer used by "go test" but preserved, as much as possible, for other
  1397  // systems that simulate "go test" using Main, but Main sometimes cannot be updated as
  1398  // new functionality is added to the testing package.
  1399  // Systems simulating "go test" should be updated to use MainStart.
  1400  func Main(matchString func(pat, str string) (bool, error), tests []InternalTest, benchmarks []InternalBenchmark, examples []InternalExample) {
  1401  	os.Exit(MainStart(matchStringOnly(matchString), tests, benchmarks, examples).Run())
  1402  }
  1403  
  1404  // M is a type passed to a TestMain function to run the actual tests.
  1405  type M struct {
  1406  	deps       testDeps
  1407  	tests      []InternalTest
  1408  	benchmarks []InternalBenchmark
  1409  	examples   []InternalExample
  1410  
  1411  	timer     *time.Timer
  1412  	afterOnce sync.Once
  1413  
  1414  	numRun int
  1415  
  1416  	// value to pass to os.Exit, the outer test func main
  1417  	// harness calls os.Exit with this code. See #34129.
  1418  	exitCode int
  1419  }
  1420  
  1421  // testDeps is an internal interface of functionality that is
  1422  // passed into this package by a test's generated main package.
  1423  // The canonical implementation of this interface is
  1424  // testing/internal/testdeps's TestDeps.
  1425  type testDeps interface {
  1426  	ImportPath() string
  1427  	MatchString(pat, str string) (bool, error)
  1428  	SetPanicOnExit0(bool)
  1429  	StartCPUProfile(io.Writer) error
  1430  	StopCPUProfile()
  1431  	StartTestLog(io.Writer)
  1432  	StopTestLog() error
  1433  	WriteProfileTo(string, io.Writer, int) error
  1434  }
  1435  
  1436  // MainStart is meant for use by tests generated by 'go test'.
  1437  // It is not meant to be called directly and is not subject to the Go 1 compatibility document.
  1438  // It may change signature from release to release.
  1439  func MainStart(deps testDeps, tests []InternalTest, benchmarks []InternalBenchmark, examples []InternalExample) *M {
  1440  	Init()
  1441  	return &M{
  1442  		deps:       deps,
  1443  		tests:      tests,
  1444  		benchmarks: benchmarks,
  1445  		examples:   examples,
  1446  	}
  1447  }
  1448  
  1449  // Run runs the tests. It returns an exit code to pass to os.Exit.
  1450  func (m *M) Run() (code int) {
  1451  	defer func() {
  1452  		code = m.exitCode
  1453  	}()
  1454  
  1455  	// Count the number of calls to m.Run.
  1456  	// We only ever expected 1, but we didn't enforce that,
  1457  	// and now there are tests in the wild that call m.Run multiple times.
  1458  	// Sigh. golang.org/issue/23129.
  1459  	m.numRun++
  1460  
  1461  	// TestMain may have already called flag.Parse.
  1462  	if !flag.Parsed() {
  1463  		flag.Parse()
  1464  	}
  1465  
  1466  	if *parallel < 1 {
  1467  		fmt.Fprintln(os.Stderr, "testing: -parallel can only be given a positive integer")
  1468  		flag.Usage()
  1469  		m.exitCode = 2
  1470  		return
  1471  	}
  1472  
  1473  	if len(*matchList) != 0 {
  1474  		listTests(m.deps.MatchString, m.tests, m.benchmarks, m.examples)
  1475  		m.exitCode = 0
  1476  		return
  1477  	}
  1478  
  1479  	if *shuffle != "off" {
  1480  		var n int64
  1481  		var err error
  1482  		if *shuffle == "on" {
  1483  			n = time.Now().UnixNano()
  1484  		} else {
  1485  			n, err = strconv.ParseInt(*shuffle, 10, 64)
  1486  			if err != nil {
  1487  				fmt.Fprintln(os.Stderr, `testing: -shuffle should be "off", "on", or a valid integer:`, err)
  1488  				m.exitCode = 2
  1489  				return
  1490  			}
  1491  		}
  1492  		fmt.Println("-test.shuffle", n)
  1493  		rng := rand.New(rand.NewSource(n))
  1494  		rng.Shuffle(len(m.tests), func(i, j int) { m.tests[i], m.tests[j] = m.tests[j], m.tests[i] })
  1495  		rng.Shuffle(len(m.benchmarks), func(i, j int) { m.benchmarks[i], m.benchmarks[j] = m.benchmarks[j], m.benchmarks[i] })
  1496  	}
  1497  
  1498  	parseCpuList()
  1499  
  1500  	m.before()
  1501  	defer m.after()
  1502  	deadline := m.startAlarm()
  1503  	haveExamples = len(m.examples) > 0
  1504  	testRan, testOk := runTests(m.deps.MatchString, m.tests, deadline)
  1505  	exampleRan, exampleOk := runExamples(m.deps.MatchString, m.examples)
  1506  	m.stopAlarm()
  1507  	if !testRan && !exampleRan && *matchBenchmarks == "" {
  1508  		fmt.Fprintln(os.Stderr, "testing: warning: no tests to run")
  1509  	}
  1510  	if !testOk || !exampleOk || !runBenchmarks(m.deps.ImportPath(), m.deps.MatchString, m.benchmarks) || race.Errors() > 0 {
  1511  		fmt.Println("FAIL")
  1512  		m.exitCode = 1
  1513  		return
  1514  	}
  1515  
  1516  	fmt.Println("PASS")
  1517  	m.exitCode = 0
  1518  	return
  1519  }
  1520  
  1521  func (t *T) report() {
  1522  	if t.parent == nil {
  1523  		return
  1524  	}
  1525  	dstr := fmtDuration(t.duration)
  1526  	format := "--- %s: %s (%s)\n"
  1527  	if t.Failed() {
  1528  		t.flushToParent(t.name, format, "FAIL", t.name, dstr)
  1529  	} else if t.chatty != nil {
  1530  		if t.Skipped() {
  1531  			t.flushToParent(t.name, format, "SKIP", t.name, dstr)
  1532  		} else {
  1533  			t.flushToParent(t.name, format, "PASS", t.name, dstr)
  1534  		}
  1535  	}
  1536  }
  1537  
  1538  func listTests(matchString func(pat, str string) (bool, error), tests []InternalTest, benchmarks []InternalBenchmark, examples []InternalExample) {
  1539  	if _, err := matchString(*matchList, "non-empty"); err != nil {
  1540  		fmt.Fprintf(os.Stderr, "testing: invalid regexp in -test.list (%q): %s\n", *matchList, err)
  1541  		os.Exit(1)
  1542  	}
  1543  
  1544  	for _, test := range tests {
  1545  		if ok, _ := matchString(*matchList, test.Name); ok {
  1546  			fmt.Println(test.Name)
  1547  		}
  1548  	}
  1549  	for _, bench := range benchmarks {
  1550  		if ok, _ := matchString(*matchList, bench.Name); ok {
  1551  			fmt.Println(bench.Name)
  1552  		}
  1553  	}
  1554  	for _, example := range examples {
  1555  		if ok, _ := matchString(*matchList, example.Name); ok {
  1556  			fmt.Println(example.Name)
  1557  		}
  1558  	}
  1559  }
  1560  
  1561  // RunTests is an internal function but exported because it is cross-package;
  1562  // it is part of the implementation of the "go test" command.
  1563  func RunTests(matchString func(pat, str string) (bool, error), tests []InternalTest) (ok bool) {
  1564  	var deadline time.Time
  1565  	if *timeout > 0 {
  1566  		deadline = time.Now().Add(*timeout)
  1567  	}
  1568  	ran, ok := runTests(matchString, tests, deadline)
  1569  	if !ran && !haveExamples {
  1570  		fmt.Fprintln(os.Stderr, "testing: warning: no tests to run")
  1571  	}
  1572  	return ok
  1573  }
  1574  
  1575  func runTests(matchString func(pat, str string) (bool, error), tests []InternalTest, deadline time.Time) (ran, ok bool) {
  1576  	ok = true
  1577  	for _, procs := range cpuList {
  1578  		runtime.GOMAXPROCS(procs)
  1579  		for i := uint(0); i < *count; i++ {
  1580  			if shouldFailFast() {
  1581  				break
  1582  			}
  1583  			ctx := newTestContext(*parallel, newMatcher(matchString, *match, "-test.run"))
  1584  			ctx.deadline = deadline
  1585  			t := &T{
  1586  				common: common{
  1587  					signal:  make(chan bool, 1),
  1588  					barrier: make(chan bool),
  1589  					w:       os.Stdout,
  1590  				},
  1591  				context: ctx,
  1592  			}
  1593  			if Verbose() {
  1594  				t.chatty = newChattyPrinter(t.w)
  1595  			}
  1596  			tRunner(t, func(t *T) {
  1597  				for _, test := range tests {
  1598  					t.Run(test.Name, test.F)
  1599  				}
  1600  			})
  1601  			select {
  1602  			case <-t.signal:
  1603  			default:
  1604  				panic("internal error: tRunner exited without sending on t.signal")
  1605  			}
  1606  			ok = ok && !t.Failed()
  1607  			ran = ran || t.ran
  1608  		}
  1609  	}
  1610  	return ran, ok
  1611  }
  1612  
  1613  // before runs before all testing.
  1614  func (m *M) before() {
  1615  	if *memProfileRate > 0 {
  1616  		runtime.MemProfileRate = *memProfileRate
  1617  	}
  1618  	if *cpuProfile != "" {
  1619  		f, err := os.Create(toOutputDir(*cpuProfile))
  1620  		if err != nil {
  1621  			fmt.Fprintf(os.Stderr, "testing: %s\n", err)
  1622  			return
  1623  		}
  1624  		if err := m.deps.StartCPUProfile(f); err != nil {
  1625  			fmt.Fprintf(os.Stderr, "testing: can't start cpu profile: %s\n", err)
  1626  			f.Close()
  1627  			return
  1628  		}
  1629  		// Could save f so after can call f.Close; not worth the effort.
  1630  	}
  1631  	if *traceFile != "" {
  1632  		f, err := os.Create(toOutputDir(*traceFile))
  1633  		if err != nil {
  1634  			fmt.Fprintf(os.Stderr, "testing: %s\n", err)
  1635  			return
  1636  		}
  1637  		if err := trace.Start(f); err != nil {
  1638  			fmt.Fprintf(os.Stderr, "testing: can't start tracing: %s\n", err)
  1639  			f.Close()
  1640  			return
  1641  		}
  1642  		// Could save f so after can call f.Close; not worth the effort.
  1643  	}
  1644  	if *blockProfile != "" && *blockProfileRate >= 0 {
  1645  		runtime.SetBlockProfileRate(*blockProfileRate)
  1646  	}
  1647  	if *mutexProfile != "" && *mutexProfileFraction >= 0 {
  1648  		runtime.SetMutexProfileFraction(*mutexProfileFraction)
  1649  	}
  1650  	if *coverProfile != "" && cover.Mode == "" {
  1651  		fmt.Fprintf(os.Stderr, "testing: cannot use -test.coverprofile because test binary was not built with coverage enabled\n")
  1652  		os.Exit(2)
  1653  	}
  1654  	if *testlog != "" {
  1655  		// Note: Not using toOutputDir.
  1656  		// This file is for use by cmd/go, not users.
  1657  		var f *os.File
  1658  		var err error
  1659  		if m.numRun == 1 {
  1660  			f, err = os.Create(*testlog)
  1661  		} else {
  1662  			f, err = os.OpenFile(*testlog, os.O_WRONLY, 0)
  1663  			if err == nil {
  1664  				f.Seek(0, io.SeekEnd)
  1665  			}
  1666  		}
  1667  		if err != nil {
  1668  			fmt.Fprintf(os.Stderr, "testing: %s\n", err)
  1669  			os.Exit(2)
  1670  		}
  1671  		m.deps.StartTestLog(f)
  1672  		testlogFile = f
  1673  	}
  1674  	if *panicOnExit0 {
  1675  		m.deps.SetPanicOnExit0(true)
  1676  	}
  1677  }
  1678  
  1679  // after runs after all testing.
  1680  func (m *M) after() {
  1681  	m.afterOnce.Do(func() {
  1682  		m.writeProfiles()
  1683  	})
  1684  
  1685  	// Restore PanicOnExit0 after every run, because we set it to true before
  1686  	// every run. Otherwise, if m.Run is called multiple times the behavior of
  1687  	// os.Exit(0) will not be restored after the second run.
  1688  	if *panicOnExit0 {
  1689  		m.deps.SetPanicOnExit0(false)
  1690  	}
  1691  }
  1692  
  1693  func (m *M) writeProfiles() {
  1694  	if *testlog != "" {
  1695  		if err := m.deps.StopTestLog(); err != nil {
  1696  			fmt.Fprintf(os.Stderr, "testing: can't write %s: %s\n", *testlog, err)
  1697  			os.Exit(2)
  1698  		}
  1699  		if err := testlogFile.Close(); err != nil {
  1700  			fmt.Fprintf(os.Stderr, "testing: can't write %s: %s\n", *testlog, err)
  1701  			os.Exit(2)
  1702  		}
  1703  	}
  1704  	if *cpuProfile != "" {
  1705  		m.deps.StopCPUProfile() // flushes profile to disk
  1706  	}
  1707  	if *traceFile != "" {
  1708  		trace.Stop() // flushes trace to disk
  1709  	}
  1710  	if *memProfile != "" {
  1711  		f, err := os.Create(toOutputDir(*memProfile))
  1712  		if err != nil {
  1713  			fmt.Fprintf(os.Stderr, "testing: %s\n", err)
  1714  			os.Exit(2)
  1715  		}
  1716  		runtime.GC() // materialize all statistics
  1717  		if err = m.deps.WriteProfileTo("allocs", f, 0); err != nil {
  1718  			fmt.Fprintf(os.Stderr, "testing: can't write %s: %s\n", *memProfile, err)
  1719  			os.Exit(2)
  1720  		}
  1721  		f.Close()
  1722  	}
  1723  	if *blockProfile != "" && *blockProfileRate >= 0 {
  1724  		f, err := os.Create(toOutputDir(*blockProfile))
  1725  		if err != nil {
  1726  			fmt.Fprintf(os.Stderr, "testing: %s\n", err)
  1727  			os.Exit(2)
  1728  		}
  1729  		if err = m.deps.WriteProfileTo("block", f, 0); err != nil {
  1730  			fmt.Fprintf(os.Stderr, "testing: can't write %s: %s\n", *blockProfile, err)
  1731  			os.Exit(2)
  1732  		}
  1733  		f.Close()
  1734  	}
  1735  	if *mutexProfile != "" && *mutexProfileFraction >= 0 {
  1736  		f, err := os.Create(toOutputDir(*mutexProfile))
  1737  		if err != nil {
  1738  			fmt.Fprintf(os.Stderr, "testing: %s\n", err)
  1739  			os.Exit(2)
  1740  		}
  1741  		if err = m.deps.WriteProfileTo("mutex", f, 0); err != nil {
  1742  			fmt.Fprintf(os.Stderr, "testing: can't write %s: %s\n", *mutexProfile, err)
  1743  			os.Exit(2)
  1744  		}
  1745  		f.Close()
  1746  	}
  1747  	if cover.Mode != "" {
  1748  		coverReport()
  1749  	}
  1750  }
  1751  
  1752  // toOutputDir returns the file name relocated, if required, to outputDir.
  1753  // Simple implementation to avoid pulling in path/filepath.
  1754  func toOutputDir(path string) string {
  1755  	if *outputDir == "" || path == "" {
  1756  		return path
  1757  	}
  1758  	// On Windows, it's clumsy, but we can be almost always correct
  1759  	// by just looking for a drive letter and a colon.
  1760  	// Absolute paths always have a drive letter (ignoring UNC).
  1761  	// Problem: if path == "C:A" and outputdir == "C:\Go" it's unclear
  1762  	// what to do, but even then path/filepath doesn't help.
  1763  	// TODO: Worth doing better? Probably not, because we're here only
  1764  	// under the management of go test.
  1765  	if runtime.GOOS == "windows" && len(path) >= 2 {
  1766  		letter, colon := path[0], path[1]
  1767  		if ('a' <= letter && letter <= 'z' || 'A' <= letter && letter <= 'Z') && colon == ':' {
  1768  			// If path starts with a drive letter we're stuck with it regardless.
  1769  			return path
  1770  		}
  1771  	}
  1772  	if os.IsPathSeparator(path[0]) {
  1773  		return path
  1774  	}
  1775  	return fmt.Sprintf("%s%c%s", *outputDir, os.PathSeparator, path)
  1776  }
  1777  
  1778  // startAlarm starts an alarm if requested.
  1779  func (m *M) startAlarm() time.Time {
  1780  	if *timeout <= 0 {
  1781  		return time.Time{}
  1782  	}
  1783  
  1784  	deadline := time.Now().Add(*timeout)
  1785  	m.timer = time.AfterFunc(*timeout, func() {
  1786  		m.after()
  1787  		debug.SetTraceback("all")
  1788  		panic(fmt.Sprintf("test timed out after %v", *timeout))
  1789  	})
  1790  	return deadline
  1791  }
  1792  
  1793  // stopAlarm turns off the alarm.
  1794  func (m *M) stopAlarm() {
  1795  	if *timeout > 0 {
  1796  		m.timer.Stop()
  1797  	}
  1798  }
  1799  
  1800  func parseCpuList() {
  1801  	for _, val := range strings.Split(*cpuListStr, ",") {
  1802  		val = strings.TrimSpace(val)
  1803  		if val == "" {
  1804  			continue
  1805  		}
  1806  		cpu, err := strconv.Atoi(val)
  1807  		if err != nil || cpu <= 0 {
  1808  			fmt.Fprintf(os.Stderr, "testing: invalid value %q for -test.cpu\n", val)
  1809  			os.Exit(1)
  1810  		}
  1811  		cpuList = append(cpuList, cpu)
  1812  	}
  1813  	if cpuList == nil {
  1814  		cpuList = append(cpuList, runtime.GOMAXPROCS(-1))
  1815  	}
  1816  }
  1817  
  1818  func shouldFailFast() bool {
  1819  	return *failFast && atomic.LoadUint32(&numFailed) > 0
  1820  }
  1821  

View as plain text