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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 8192 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 program to do extra setup or teardown
   212  // before or after testing. It is also sometimes necessary for a test 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
   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  package testing
   237  
   238  import (
   239  	"bytes"
   240  	"errors"
   241  	"flag"
   242  	"fmt"
   243  	"internal/race"
   244  	"io"
   245  	"io/ioutil"
   246  	"os"
   247  	"runtime"
   248  	"runtime/debug"
   249  	"runtime/trace"
   250  	"strconv"
   251  	"strings"
   252  	"sync"
   253  	"sync/atomic"
   254  	"time"
   255  )
   256  
   257  var initRan bool
   258  
   259  // Init registers testing flags. These flags are automatically registered by
   260  // the "go test" command before running test functions, so Init is only needed
   261  // when calling functions such as Benchmark without using "go test".
   262  //
   263  // Init has no effect if it was already called.
   264  func Init() {
   265  	if initRan {
   266  		return
   267  	}
   268  	initRan = true
   269  	// The short flag requests that tests run more quickly, but its functionality
   270  	// is provided by test writers themselves. The testing package is just its
   271  	// home. The all.bash installation script sets it to make installation more
   272  	// efficient, but by default the flag is off so a plain "go test" will do a
   273  	// full test of the package.
   274  	short = flag.Bool("test.short", false, "run smaller test suite to save time")
   275  
   276  	// The failfast flag requests that test execution stop after the first test failure.
   277  	failFast = flag.Bool("test.failfast", false, "do not start new tests after the first test failure")
   278  
   279  	// The directory in which to create profile files and the like. When run from
   280  	// "go test", the binary always runs in the source directory for the package;
   281  	// this flag lets "go test" tell the binary to write the files in the directory where
   282  	// the "go test" command is run.
   283  	outputDir = flag.String("test.outputdir", "", "write profiles to `dir`")
   284  	// Report as tests are run; default is silent for success.
   285  	chatty = flag.Bool("test.v", false, "verbose: print additional output")
   286  	count = flag.Uint("test.count", 1, "run tests and benchmarks `n` times")
   287  	coverProfile = flag.String("test.coverprofile", "", "write a coverage profile to `file`")
   288  	matchList = flag.String("test.list", "", "list tests, examples, and benchmarks matching `regexp` then exit")
   289  	match = flag.String("test.run", "", "run only tests and examples matching `regexp`")
   290  	memProfile = flag.String("test.memprofile", "", "write an allocation profile to `file`")
   291  	memProfileRate = flag.Int("test.memprofilerate", 0, "set memory allocation profiling `rate` (see runtime.MemProfileRate)")
   292  	cpuProfile = flag.String("test.cpuprofile", "", "write a cpu profile to `file`")
   293  	blockProfile = flag.String("test.blockprofile", "", "write a goroutine blocking profile to `file`")
   294  	blockProfileRate = flag.Int("test.blockprofilerate", 1, "set blocking profile `rate` (see runtime.SetBlockProfileRate)")
   295  	mutexProfile = flag.String("test.mutexprofile", "", "write a mutex contention profile to the named file after execution")
   296  	mutexProfileFraction = flag.Int("test.mutexprofilefraction", 1, "if >= 0, calls runtime.SetMutexProfileFraction()")
   297  	traceFile = flag.String("test.trace", "", "write an execution trace to `file`")
   298  	timeout = flag.Duration("test.timeout", 0, "panic test binary after duration `d` (default 0, timeout disabled)")
   299  	cpuListStr = flag.String("test.cpu", "", "comma-separated `list` of cpu counts to run each test with")
   300  	parallel = flag.Int("test.parallel", runtime.GOMAXPROCS(0), "run at most `n` tests in parallel")
   301  	testlog = flag.String("test.testlogfile", "", "write test action log to `file` (for use only by cmd/go)")
   302  
   303  	initBenchmarkFlags()
   304  }
   305  
   306  var (
   307  	// Flags, registered during Init.
   308  	short                *bool
   309  	failFast             *bool
   310  	outputDir            *string
   311  	chatty               *bool
   312  	count                *uint
   313  	coverProfile         *string
   314  	matchList            *string
   315  	match                *string
   316  	memProfile           *string
   317  	memProfileRate       *int
   318  	cpuProfile           *string
   319  	blockProfile         *string
   320  	blockProfileRate     *int
   321  	mutexProfile         *string
   322  	mutexProfileFraction *int
   323  	traceFile            *string
   324  	timeout              *time.Duration
   325  	cpuListStr           *string
   326  	parallel             *int
   327  	testlog              *string
   328  
   329  	haveExamples bool // are there examples?
   330  
   331  	cpuList     []int
   332  	testlogFile *os.File
   333  
   334  	numFailed uint32 // number of test failures
   335  )
   336  
   337  type chattyPrinter struct {
   338  	w          io.Writer
   339  	lastNameMu sync.Mutex // guards lastName
   340  	lastName   string     // last printed test name in chatty mode
   341  }
   342  
   343  func newChattyPrinter(w io.Writer) *chattyPrinter {
   344  	return &chattyPrinter{w: w}
   345  }
   346  
   347  // Updatef prints a message about the status of the named test to w.
   348  //
   349  // The formatted message must include the test name itself.
   350  func (p *chattyPrinter) Updatef(testName, format string, args ...interface{}) {
   351  	p.lastNameMu.Lock()
   352  	defer p.lastNameMu.Unlock()
   353  
   354  	// Since the message already implies an association with a specific new test,
   355  	// we don't need to check what the old test name was or log an extra CONT line
   356  	// for it. (We're updating it anyway, and the current message already includes
   357  	// the test name.)
   358  	p.lastName = testName
   359  	fmt.Fprintf(p.w, format, args...)
   360  }
   361  
   362  // Printf prints a message, generated by the named test, that does not
   363  // necessarily mention that tests's name itself.
   364  func (p *chattyPrinter) Printf(testName, format string, args ...interface{}) {
   365  	p.lastNameMu.Lock()
   366  	defer p.lastNameMu.Unlock()
   367  
   368  	if p.lastName == "" {
   369  		p.lastName = testName
   370  	} else if p.lastName != testName {
   371  		fmt.Fprintf(p.w, "=== CONT  %s\n", testName)
   372  		p.lastName = testName
   373  	}
   374  
   375  	fmt.Fprintf(p.w, format, args...)
   376  }
   377  
   378  // The maximum number of stack frames to go through when skipping helper functions for
   379  // the purpose of decorating log messages.
   380  const maxStackLen = 50
   381  
   382  // common holds the elements common between T and B and
   383  // captures common methods such as Errorf.
   384  type common struct {
   385  	mu          sync.RWMutex        // guards this group of fields
   386  	output      []byte              // Output generated by test or benchmark.
   387  	w           io.Writer           // For flushToParent.
   388  	ran         bool                // Test or benchmark (or one of its subtests) was executed.
   389  	failed      bool                // Test or benchmark has failed.
   390  	skipped     bool                // Test of benchmark has been skipped.
   391  	done        bool                // Test is finished and all subtests have completed.
   392  	helpers     map[string]struct{} // functions to be skipped when writing file/line info
   393  	cleanup     func()              // optional function to be called at the end of the test
   394  	cleanupName string              // Name of the cleanup function.
   395  	cleanupPc   []uintptr           // The stack trace at the point where Cleanup was called.
   396  
   397  	chatty     *chattyPrinter // A copy of chattyPrinter, if the chatty flag is set.
   398  	bench      bool           // Whether the current test is a benchmark.
   399  	finished   bool           // Test function has completed.
   400  	hasSub     int32          // Written atomically.
   401  	raceErrors int            // Number of races detected during test.
   402  	runner     string         // Function name of tRunner running the test.
   403  
   404  	parent   *common
   405  	level    int       // Nesting depth of test or benchmark.
   406  	creator  []uintptr // If level > 0, the stack trace at the point where the parent called t.Run.
   407  	name     string    // Name of test or benchmark.
   408  	start    time.Time // Time test or benchmark started
   409  	duration time.Duration
   410  	barrier  chan bool // To signal parallel subtests they may start.
   411  	signal   chan bool // To signal a test is done.
   412  	sub      []*T      // Queue of subtests to be run in parallel.
   413  
   414  	tempDirOnce sync.Once
   415  	tempDir     string
   416  	tempDirErr  error
   417  	tempDirSeq  int32
   418  }
   419  
   420  // Short reports whether the -test.short flag is set.
   421  func Short() bool {
   422  	if short == nil {
   423  		panic("testing: Short called before Init")
   424  	}
   425  	// Catch code that calls this from TestMain without first calling flag.Parse.
   426  	if !flag.Parsed() {
   427  		panic("testing: Short called before Parse")
   428  	}
   429  
   430  	return *short
   431  }
   432  
   433  // CoverMode reports what the test coverage mode is set to. The
   434  // values are "set", "count", or "atomic". The return value will be
   435  // empty if test coverage is not enabled.
   436  func CoverMode() string {
   437  	return cover.Mode
   438  }
   439  
   440  // Verbose reports whether the -test.v flag is set.
   441  func Verbose() bool {
   442  	// Same as in Short.
   443  	if chatty == nil {
   444  		panic("testing: Verbose called before Init")
   445  	}
   446  	if !flag.Parsed() {
   447  		panic("testing: Verbose called before Parse")
   448  	}
   449  	return *chatty
   450  }
   451  
   452  // frameSkip searches, starting after skip frames, for the first caller frame
   453  // in a function not marked as a helper and returns that frame.
   454  // The search stops if it finds a tRunner function that
   455  // was the entry point into the test and the test is not a subtest.
   456  // This function must be called with c.mu held.
   457  func (c *common) frameSkip(skip int) runtime.Frame {
   458  	// If the search continues into the parent test, we'll have to hold
   459  	// its mu temporarily. If we then return, we need to unlock it.
   460  	shouldUnlock := false
   461  	defer func() {
   462  		if shouldUnlock {
   463  			c.mu.Unlock()
   464  		}
   465  	}()
   466  	var pc [maxStackLen]uintptr
   467  	// Skip two extra frames to account for this function
   468  	// and runtime.Callers itself.
   469  	n := runtime.Callers(skip+2, pc[:])
   470  	if n == 0 {
   471  		panic("testing: zero callers found")
   472  	}
   473  	frames := runtime.CallersFrames(pc[:n])
   474  	var firstFrame, prevFrame, frame runtime.Frame
   475  	for more := true; more; prevFrame = frame {
   476  		frame, more = frames.Next()
   477  		if frame.Function == c.cleanupName {
   478  			frames = runtime.CallersFrames(c.cleanupPc)
   479  			continue
   480  		}
   481  		if firstFrame.PC == 0 {
   482  			firstFrame = frame
   483  		}
   484  		if frame.Function == c.runner {
   485  			// We've gone up all the way to the tRunner calling
   486  			// the test function (so the user must have
   487  			// called tb.Helper from inside that test function).
   488  			// If this is a top-level test, only skip up to the test function itself.
   489  			// If we're in a subtest, continue searching in the parent test,
   490  			// starting from the point of the call to Run which created this subtest.
   491  			if c.level > 1 {
   492  				frames = runtime.CallersFrames(c.creator)
   493  				parent := c.parent
   494  				// We're no longer looking at the current c after this point,
   495  				// so we should unlock its mu, unless it's the original receiver,
   496  				// in which case our caller doesn't expect us to do that.
   497  				if shouldUnlock {
   498  					c.mu.Unlock()
   499  				}
   500  				c = parent
   501  				// Remember to unlock c.mu when we no longer need it, either
   502  				// because we went up another nesting level, or because we
   503  				// returned.
   504  				shouldUnlock = true
   505  				c.mu.Lock()
   506  				continue
   507  			}
   508  			return prevFrame
   509  		}
   510  		if _, ok := c.helpers[frame.Function]; !ok {
   511  			// Found a frame that wasn't inside a helper function.
   512  			return frame
   513  		}
   514  	}
   515  	return firstFrame
   516  }
   517  
   518  // decorate prefixes the string with the file and line of the call site
   519  // and inserts the final newline if needed and indentation spaces for formatting.
   520  // This function must be called with c.mu held.
   521  func (c *common) decorate(s string, skip int) string {
   522  	frame := c.frameSkip(skip)
   523  	file := frame.File
   524  	line := frame.Line
   525  	if file != "" {
   526  		// Truncate file name at last file name separator.
   527  		if index := strings.LastIndex(file, "/"); index >= 0 {
   528  			file = file[index+1:]
   529  		} else if index = strings.LastIndex(file, "\\"); index >= 0 {
   530  			file = file[index+1:]
   531  		}
   532  	} else {
   533  		file = "???"
   534  	}
   535  	if line == 0 {
   536  		line = 1
   537  	}
   538  	buf := new(strings.Builder)
   539  	// Every line is indented at least 4 spaces.
   540  	buf.WriteString("    ")
   541  	fmt.Fprintf(buf, "%s:%d: ", file, line)
   542  	lines := strings.Split(s, "\n")
   543  	if l := len(lines); l > 1 && lines[l-1] == "" {
   544  		lines = lines[:l-1]
   545  	}
   546  	for i, line := range lines {
   547  		if i > 0 {
   548  			// Second and subsequent lines are indented an additional 4 spaces.
   549  			buf.WriteString("\n        ")
   550  		}
   551  		buf.WriteString(line)
   552  	}
   553  	buf.WriteByte('\n')
   554  	return buf.String()
   555  }
   556  
   557  // flushToParent writes c.output to the parent after first writing the header
   558  // with the given format and arguments.
   559  func (c *common) flushToParent(testName, format string, args ...interface{}) {
   560  	p := c.parent
   561  	p.mu.Lock()
   562  	defer p.mu.Unlock()
   563  
   564  	c.mu.Lock()
   565  	defer c.mu.Unlock()
   566  
   567  	if len(c.output) > 0 {
   568  		format += "%s"
   569  		args = append(args[:len(args):len(args)], c.output)
   570  		c.output = c.output[:0] // but why?
   571  	}
   572  
   573  	if c.chatty != nil && p.w == c.chatty.w {
   574  		// We're flushing to the actual output, so track that this output is
   575  		// associated with a specific test (and, specifically, that the next output
   576  		// is *not* associated with that test).
   577  		//
   578  		// Moreover, if c.output is non-empty it is important that this write be
   579  		// atomic with respect to the output of other tests, so that we don't end up
   580  		// with confusing '=== CONT' lines in the middle of our '--- PASS' block.
   581  		// Neither humans nor cmd/test2json can parse those easily.
   582  		// (See https://golang.org/issue/40771.)
   583  		c.chatty.Updatef(testName, format, args...)
   584  	} else {
   585  		// We're flushing to the output buffer of the parent test, which will
   586  		// itself follow a test-name header when it is finally flushed to stdout.
   587  		fmt.Fprintf(p.w, format, args...)
   588  	}
   589  }
   590  
   591  type indenter struct {
   592  	c *common
   593  }
   594  
   595  func (w indenter) Write(b []byte) (n int, err error) {
   596  	n = len(b)
   597  	for len(b) > 0 {
   598  		end := bytes.IndexByte(b, '\n')
   599  		if end == -1 {
   600  			end = len(b)
   601  		} else {
   602  			end++
   603  		}
   604  		// An indent of 4 spaces will neatly align the dashes with the status
   605  		// indicator of the parent.
   606  		const indent = "    "
   607  		w.c.output = append(w.c.output, indent...)
   608  		w.c.output = append(w.c.output, b[:end]...)
   609  		b = b[end:]
   610  	}
   611  	return
   612  }
   613  
   614  // fmtDuration returns a string representing d in the form "87.00s".
   615  func fmtDuration(d time.Duration) string {
   616  	return fmt.Sprintf("%.2fs", d.Seconds())
   617  }
   618  
   619  // TB is the interface common to T and B.
   620  type TB interface {
   621  	Cleanup(func())
   622  	Error(args ...interface{})
   623  	Errorf(format string, args ...interface{})
   624  	Fail()
   625  	FailNow()
   626  	Failed() bool
   627  	Fatal(args ...interface{})
   628  	Fatalf(format string, args ...interface{})
   629  	Helper()
   630  	Log(args ...interface{})
   631  	Logf(format string, args ...interface{})
   632  	Name() string
   633  	Skip(args ...interface{})
   634  	SkipNow()
   635  	Skipf(format string, args ...interface{})
   636  	Skipped() bool
   637  	TempDir() string
   638  
   639  	// A private method to prevent users implementing the
   640  	// interface and so future additions to it will not
   641  	// violate Go 1 compatibility.
   642  	private()
   643  }
   644  
   645  var _ TB = (*T)(nil)
   646  var _ TB = (*B)(nil)
   647  
   648  // T is a type passed to Test functions to manage test state and support formatted test logs.
   649  //
   650  // A test ends when its Test function returns or calls any of the methods
   651  // FailNow, Fatal, Fatalf, SkipNow, Skip, or Skipf. Those methods, as well as
   652  // the Parallel method, must be called only from the goroutine running the
   653  // Test function.
   654  //
   655  // The other reporting methods, such as the variations of Log and Error,
   656  // may be called simultaneously from multiple goroutines.
   657  type T struct {
   658  	common
   659  	isParallel bool
   660  	context    *testContext // For running tests and subtests.
   661  }
   662  
   663  func (c *common) private() {}
   664  
   665  // Name returns the name of the running test or benchmark.
   666  func (c *common) Name() string {
   667  	return c.name
   668  }
   669  
   670  func (c *common) setRan() {
   671  	if c.parent != nil {
   672  		c.parent.setRan()
   673  	}
   674  	c.mu.Lock()
   675  	defer c.mu.Unlock()
   676  	c.ran = true
   677  }
   678  
   679  // Fail marks the function as having failed but continues execution.
   680  func (c *common) Fail() {
   681  	if c.parent != nil {
   682  		c.parent.Fail()
   683  	}
   684  	c.mu.Lock()
   685  	defer c.mu.Unlock()
   686  	// c.done needs to be locked to synchronize checks to c.done in parent tests.
   687  	if c.done {
   688  		panic("Fail in goroutine after " + c.name + " has completed")
   689  	}
   690  	c.failed = true
   691  }
   692  
   693  // Failed reports whether the function has failed.
   694  func (c *common) Failed() bool {
   695  	c.mu.RLock()
   696  	failed := c.failed
   697  	c.mu.RUnlock()
   698  	return failed || c.raceErrors+race.Errors() > 0
   699  }
   700  
   701  // FailNow marks the function as having failed and stops its execution
   702  // by calling runtime.Goexit (which then runs all deferred calls in the
   703  // current goroutine).
   704  // Execution will continue at the next test or benchmark.
   705  // FailNow must be called from the goroutine running the
   706  // test or benchmark function, not from other goroutines
   707  // created during the test. Calling FailNow does not stop
   708  // those other goroutines.
   709  func (c *common) FailNow() {
   710  	c.Fail()
   711  
   712  	// Calling runtime.Goexit will exit the goroutine, which
   713  	// will run the deferred functions in this goroutine,
   714  	// which will eventually run the deferred lines in tRunner,
   715  	// which will signal to the test loop that this test is done.
   716  	//
   717  	// A previous version of this code said:
   718  	//
   719  	//	c.duration = ...
   720  	//	c.signal <- c.self
   721  	//	runtime.Goexit()
   722  	//
   723  	// This previous version duplicated code (those lines are in
   724  	// tRunner no matter what), but worse the goroutine teardown
   725  	// implicit in runtime.Goexit was not guaranteed to complete
   726  	// before the test exited. If a test deferred an important cleanup
   727  	// function (like removing temporary files), there was no guarantee
   728  	// it would run on a test failure. Because we send on c.signal during
   729  	// a top-of-stack deferred function now, we know that the send
   730  	// only happens after any other stacked defers have completed.
   731  	c.finished = true
   732  	runtime.Goexit()
   733  }
   734  
   735  // log generates the output. It's always at the same stack depth.
   736  func (c *common) log(s string) {
   737  	c.logDepth(s, 3) // logDepth + log + public function
   738  }
   739  
   740  // logDepth generates the output at an arbitrary stack depth.
   741  func (c *common) logDepth(s string, depth int) {
   742  	c.mu.Lock()
   743  	defer c.mu.Unlock()
   744  	if c.done {
   745  		// This test has already finished. Try and log this message
   746  		// with our parent. If we don't have a parent, panic.
   747  		for parent := c.parent; parent != nil; parent = parent.parent {
   748  			parent.mu.Lock()
   749  			defer parent.mu.Unlock()
   750  			if !parent.done {
   751  				parent.output = append(parent.output, parent.decorate(s, depth+1)...)
   752  				return
   753  			}
   754  		}
   755  		panic("Log in goroutine after " + c.name + " has completed")
   756  	} else {
   757  		if c.chatty != nil {
   758  			if c.bench {
   759  				// Benchmarks don't print === CONT, so we should skip the test
   760  				// printer and just print straight to stdout.
   761  				fmt.Print(c.decorate(s, depth+1))
   762  			} else {
   763  				c.chatty.Printf(c.name, "%s", c.decorate(s, depth+1))
   764  			}
   765  
   766  			return
   767  		}
   768  		c.output = append(c.output, c.decorate(s, depth+1)...)
   769  	}
   770  }
   771  
   772  // Log formats its arguments using default formatting, analogous to Println,
   773  // and records the text in the error log. For tests, the text will be printed only if
   774  // the test fails or the -test.v flag is set. For benchmarks, the text is always
   775  // printed to avoid having performance depend on the value of the -test.v flag.
   776  func (c *common) Log(args ...interface{}) { c.log(fmt.Sprintln(args...)) }
   777  
   778  // Logf formats its arguments according to the format, analogous to Printf, and
   779  // records the text in the error log. A final newline is added if not provided. For
   780  // tests, the text will be printed only if the test fails or the -test.v flag is
   781  // set. For benchmarks, the text is always printed to avoid having performance
   782  // depend on the value of the -test.v flag.
   783  func (c *common) Logf(format string, args ...interface{}) { c.log(fmt.Sprintf(format, args...)) }
   784  
   785  // Error is equivalent to Log followed by Fail.
   786  func (c *common) Error(args ...interface{}) {
   787  	c.log(fmt.Sprintln(args...))
   788  	c.Fail()
   789  }
   790  
   791  // Errorf is equivalent to Logf followed by Fail.
   792  func (c *common) Errorf(format string, args ...interface{}) {
   793  	c.log(fmt.Sprintf(format, args...))
   794  	c.Fail()
   795  }
   796  
   797  // Fatal is equivalent to Log followed by FailNow.
   798  func (c *common) Fatal(args ...interface{}) {
   799  	c.log(fmt.Sprintln(args...))
   800  	c.FailNow()
   801  }
   802  
   803  // Fatalf is equivalent to Logf followed by FailNow.
   804  func (c *common) Fatalf(format string, args ...interface{}) {
   805  	c.log(fmt.Sprintf(format, args...))
   806  	c.FailNow()
   807  }
   808  
   809  // Skip is equivalent to Log followed by SkipNow.
   810  func (c *common) Skip(args ...interface{}) {
   811  	c.log(fmt.Sprintln(args...))
   812  	c.SkipNow()
   813  }
   814  
   815  // Skipf is equivalent to Logf followed by SkipNow.
   816  func (c *common) Skipf(format string, args ...interface{}) {
   817  	c.log(fmt.Sprintf(format, args...))
   818  	c.SkipNow()
   819  }
   820  
   821  // SkipNow marks the test as having been skipped and stops its execution
   822  // by calling runtime.Goexit.
   823  // If a test fails (see Error, Errorf, Fail) and is then skipped,
   824  // it is still considered to have failed.
   825  // Execution will continue at the next test or benchmark. See also FailNow.
   826  // SkipNow must be called from the goroutine running the test, not from
   827  // other goroutines created during the test. Calling SkipNow does not stop
   828  // those other goroutines.
   829  func (c *common) SkipNow() {
   830  	c.skip()
   831  	c.finished = true
   832  	runtime.Goexit()
   833  }
   834  
   835  func (c *common) skip() {
   836  	c.mu.Lock()
   837  	defer c.mu.Unlock()
   838  	c.skipped = true
   839  }
   840  
   841  // Skipped reports whether the test was skipped.
   842  func (c *common) Skipped() bool {
   843  	c.mu.RLock()
   844  	defer c.mu.RUnlock()
   845  	return c.skipped
   846  }
   847  
   848  // Helper marks the calling function as a test helper function.
   849  // When printing file and line information, that function will be skipped.
   850  // Helper may be called simultaneously from multiple goroutines.
   851  func (c *common) Helper() {
   852  	c.mu.Lock()
   853  	defer c.mu.Unlock()
   854  	if c.helpers == nil {
   855  		c.helpers = make(map[string]struct{})
   856  	}
   857  	c.helpers[callerName(1)] = struct{}{}
   858  }
   859  
   860  // Cleanup registers a function to be called when the test and all its
   861  // subtests complete. Cleanup functions will be called in last added,
   862  // first called order.
   863  func (c *common) Cleanup(f func()) {
   864  	c.mu.Lock()
   865  	defer c.mu.Unlock()
   866  	oldCleanup := c.cleanup
   867  	oldCleanupPc := c.cleanupPc
   868  	c.cleanup = func() {
   869  		if oldCleanup != nil {
   870  			defer func() {
   871  				c.mu.Lock()
   872  				c.cleanupPc = oldCleanupPc
   873  				c.mu.Unlock()
   874  				oldCleanup()
   875  			}()
   876  		}
   877  		c.mu.Lock()
   878  		c.cleanupName = callerName(0)
   879  		c.mu.Unlock()
   880  		f()
   881  	}
   882  	var pc [maxStackLen]uintptr
   883  	// Skip two extra frames to account for this function and runtime.Callers itself.
   884  	n := runtime.Callers(2, pc[:])
   885  	c.cleanupPc = pc[:n]
   886  }
   887  
   888  var tempDirReplacer struct {
   889  	sync.Once
   890  	r *strings.Replacer
   891  }
   892  
   893  // TempDir returns a temporary directory for the test to use.
   894  // The directory is automatically removed by Cleanup when the test and
   895  // all its subtests complete.
   896  // Each subsequent call to t.TempDir returns a unique directory;
   897  // if the directory creation fails, TempDir terminates the test by calling Fatal.
   898  func (c *common) TempDir() string {
   899  	// Use a single parent directory for all the temporary directories
   900  	// created by a test, each numbered sequentially.
   901  	c.tempDirOnce.Do(func() {
   902  		c.Helper()
   903  
   904  		// ioutil.TempDir doesn't like path separators in its pattern,
   905  		// so mangle the name to accommodate subtests.
   906  		tempDirReplacer.Do(func() {
   907  			tempDirReplacer.r = strings.NewReplacer("/", "_", "\\", "_", ":", "_")
   908  		})
   909  		pattern := tempDirReplacer.r.Replace(c.Name())
   910  
   911  		c.tempDir, c.tempDirErr = ioutil.TempDir("", pattern)
   912  		if c.tempDirErr == nil {
   913  			c.Cleanup(func() {
   914  				if err := os.RemoveAll(c.tempDir); err != nil {
   915  					c.Errorf("TempDir RemoveAll cleanup: %v", err)
   916  				}
   917  			})
   918  		}
   919  	})
   920  	if c.tempDirErr != nil {
   921  		c.Fatalf("TempDir: %v", c.tempDirErr)
   922  	}
   923  	seq := atomic.AddInt32(&c.tempDirSeq, 1)
   924  	dir := fmt.Sprintf("%s%c%03d", c.tempDir, os.PathSeparator, seq)
   925  	if err := os.Mkdir(dir, 0777); err != nil {
   926  		c.Fatalf("TempDir: %v", err)
   927  	}
   928  	return dir
   929  }
   930  
   931  // panicHanding is an argument to runCleanup.
   932  type panicHandling int
   933  
   934  const (
   935  	normalPanic panicHandling = iota
   936  	recoverAndReturnPanic
   937  )
   938  
   939  // runCleanup is called at the end of the test.
   940  // If catchPanic is true, this will catch panics, and return the recovered
   941  // value if any.
   942  func (c *common) runCleanup(ph panicHandling) (panicVal interface{}) {
   943  	c.mu.Lock()
   944  	cleanup := c.cleanup
   945  	c.cleanup = nil
   946  	c.mu.Unlock()
   947  	if cleanup == nil {
   948  		return nil
   949  	}
   950  
   951  	if ph == recoverAndReturnPanic {
   952  		defer func() {
   953  			panicVal = recover()
   954  		}()
   955  	}
   956  
   957  	cleanup()
   958  	return nil
   959  }
   960  
   961  // callerName gives the function name (qualified with a package path)
   962  // for the caller after skip frames (where 0 means the current function).
   963  func callerName(skip int) string {
   964  	// Make room for the skip PC.
   965  	var pc [1]uintptr
   966  	n := runtime.Callers(skip+2, pc[:]) // skip + runtime.Callers + callerName
   967  	if n == 0 {
   968  		panic("testing: zero callers found")
   969  	}
   970  	frames := runtime.CallersFrames(pc[:n])
   971  	frame, _ := frames.Next()
   972  	return frame.Function
   973  }
   974  
   975  // Parallel signals that this test is to be run in parallel with (and only with)
   976  // other parallel tests. When a test is run multiple times due to use of
   977  // -test.count or -test.cpu, multiple instances of a single test never run in
   978  // parallel with each other.
   979  func (t *T) Parallel() {
   980  	if t.isParallel {
   981  		panic("testing: t.Parallel called multiple times")
   982  	}
   983  	t.isParallel = true
   984  
   985  	// We don't want to include the time we spend waiting for serial tests
   986  	// in the test duration. Record the elapsed time thus far and reset the
   987  	// timer afterwards.
   988  	t.duration += time.Since(t.start)
   989  
   990  	// Add to the list of tests to be released by the parent.
   991  	t.parent.sub = append(t.parent.sub, t)
   992  	t.raceErrors += race.Errors()
   993  
   994  	if t.chatty != nil {
   995  		// Unfortunately, even though PAUSE indicates that the named test is *no
   996  		// longer* running, cmd/test2json interprets it as changing the active test
   997  		// for the purpose of log parsing. We could fix cmd/test2json, but that
   998  		// won't fix existing deployments of third-party tools that already shell
   999  		// out to older builds of cmd/test2json — so merely fixing cmd/test2json
  1000  		// isn't enough for now.
  1001  		t.chatty.Updatef(t.name, "=== PAUSE %s\n", t.name)
  1002  	}
  1003  
  1004  	t.signal <- true   // Release calling test.
  1005  	<-t.parent.barrier // Wait for the parent test to complete.
  1006  	t.context.waitParallel()
  1007  
  1008  	if t.chatty != nil {
  1009  		t.chatty.Updatef(t.name, "=== CONT  %s\n", t.name)
  1010  	}
  1011  
  1012  	t.start = time.Now()
  1013  	t.raceErrors += -race.Errors()
  1014  }
  1015  
  1016  // InternalTest is an internal type but exported because it is cross-package;
  1017  // it is part of the implementation of the "go test" command.
  1018  type InternalTest struct {
  1019  	Name string
  1020  	F    func(*T)
  1021  }
  1022  
  1023  var errNilPanicOrGoexit = errors.New("test executed panic(nil) or runtime.Goexit")
  1024  
  1025  func tRunner(t *T, fn func(t *T)) {
  1026  	t.runner = callerName(0)
  1027  
  1028  	// When this goroutine is done, either because fn(t)
  1029  	// returned normally or because a test failure triggered
  1030  	// a call to runtime.Goexit, record the duration and send
  1031  	// a signal saying that the test is done.
  1032  	defer func() {
  1033  		if t.Failed() {
  1034  			atomic.AddUint32(&numFailed, 1)
  1035  		}
  1036  
  1037  		if t.raceErrors+race.Errors() > 0 {
  1038  			t.Errorf("race detected during execution of test")
  1039  		}
  1040  
  1041  		// If the test panicked, print any test output before dying.
  1042  		err := recover()
  1043  		signal := true
  1044  		if !t.finished && err == nil {
  1045  			err = errNilPanicOrGoexit
  1046  			for p := t.parent; p != nil; p = p.parent {
  1047  				if p.finished {
  1048  					t.Errorf("%v: subtest may have called FailNow on a parent test", err)
  1049  					err = nil
  1050  					signal = false
  1051  					break
  1052  				}
  1053  			}
  1054  		}
  1055  
  1056  		doPanic := func(err interface{}) {
  1057  			t.Fail()
  1058  			if r := t.runCleanup(recoverAndReturnPanic); r != nil {
  1059  				t.Logf("cleanup panicked with %v", r)
  1060  			}
  1061  			// Flush the output log up to the root before dying.
  1062  			for root := &t.common; root.parent != nil; root = root.parent {
  1063  				root.mu.Lock()
  1064  				root.duration += time.Since(root.start)
  1065  				d := root.duration
  1066  				root.mu.Unlock()
  1067  				root.flushToParent(root.name, "--- FAIL: %s (%s)\n", root.name, fmtDuration(d))
  1068  				if r := root.parent.runCleanup(recoverAndReturnPanic); r != nil {
  1069  					fmt.Fprintf(root.parent.w, "cleanup panicked with %v", r)
  1070  				}
  1071  			}
  1072  			panic(err)
  1073  		}
  1074  		if err != nil {
  1075  			doPanic(err)
  1076  		}
  1077  
  1078  		t.duration += time.Since(t.start)
  1079  
  1080  		if len(t.sub) > 0 {
  1081  			// Run parallel subtests.
  1082  			// Decrease the running count for this test.
  1083  			t.context.release()
  1084  			// Release the parallel subtests.
  1085  			close(t.barrier)
  1086  			// Wait for subtests to complete.
  1087  			for _, sub := range t.sub {
  1088  				<-sub.signal
  1089  			}
  1090  			cleanupStart := time.Now()
  1091  			err := t.runCleanup(recoverAndReturnPanic)
  1092  			t.duration += time.Since(cleanupStart)
  1093  			if err != nil {
  1094  				doPanic(err)
  1095  			}
  1096  			if !t.isParallel {
  1097  				// Reacquire the count for sequential tests. See comment in Run.
  1098  				t.context.waitParallel()
  1099  			}
  1100  		} else if t.isParallel {
  1101  			// Only release the count for this test if it was run as a parallel
  1102  			// test. See comment in Run method.
  1103  			t.context.release()
  1104  		}
  1105  		t.report() // Report after all subtests have finished.
  1106  
  1107  		// Do not lock t.done to allow race detector to detect race in case
  1108  		// the user does not appropriately synchronizes a goroutine.
  1109  		t.done = true
  1110  		if t.parent != nil && atomic.LoadInt32(&t.hasSub) == 0 {
  1111  			t.setRan()
  1112  		}
  1113  		t.signal <- signal
  1114  	}()
  1115  	defer func() {
  1116  		if len(t.sub) == 0 {
  1117  			t.runCleanup(normalPanic)
  1118  		}
  1119  	}()
  1120  
  1121  	t.start = time.Now()
  1122  	t.raceErrors = -race.Errors()
  1123  	fn(t)
  1124  
  1125  	// code beyond here will not be executed when FailNow is invoked
  1126  	t.finished = true
  1127  }
  1128  
  1129  // Run runs f as a subtest of t called name. It runs f in a separate goroutine
  1130  // and blocks until f returns or calls t.Parallel to become a parallel test.
  1131  // Run reports whether f succeeded (or at least did not fail before calling t.Parallel).
  1132  //
  1133  // Run may be called simultaneously from multiple goroutines, but all such calls
  1134  // must return before the outer test function for t returns.
  1135  func (t *T) Run(name string, f func(t *T)) bool {
  1136  	atomic.StoreInt32(&t.hasSub, 1)
  1137  	testName, ok, _ := t.context.match.fullName(&t.common, name)
  1138  	if !ok || shouldFailFast() {
  1139  		return true
  1140  	}
  1141  	// Record the stack trace at the point of this call so that if the subtest
  1142  	// function - which runs in a separate stack - is marked as a helper, we can
  1143  	// continue walking the stack into the parent test.
  1144  	var pc [maxStackLen]uintptr
  1145  	n := runtime.Callers(2, pc[:])
  1146  	t = &T{
  1147  		common: common{
  1148  			barrier: make(chan bool),
  1149  			signal:  make(chan bool),
  1150  			name:    testName,
  1151  			parent:  &t.common,
  1152  			level:   t.level + 1,
  1153  			creator: pc[:n],
  1154  			chatty:  t.chatty,
  1155  		},
  1156  		context: t.context,
  1157  	}
  1158  	t.w = indenter{&t.common}
  1159  
  1160  	if t.chatty != nil {
  1161  		t.chatty.Updatef(t.name, "=== RUN   %s\n", t.name)
  1162  	}
  1163  	// Instead of reducing the running count of this test before calling the
  1164  	// tRunner and increasing it afterwards, we rely on tRunner keeping the
  1165  	// count correct. This ensures that a sequence of sequential tests runs
  1166  	// without being preempted, even when their parent is a parallel test. This
  1167  	// may especially reduce surprises if *parallel == 1.
  1168  	go tRunner(t, f)
  1169  	if !<-t.signal {
  1170  		// At this point, it is likely that FailNow was called on one of the
  1171  		// parent tests by one of the subtests. Continue aborting up the chain.
  1172  		runtime.Goexit()
  1173  	}
  1174  	return !t.failed
  1175  }
  1176  
  1177  // Deadline reports the time at which the test binary will have
  1178  // exceeded the timeout specified by the -timeout flag.
  1179  //
  1180  // The ok result is false if the -timeout flag indicates “no timeout” (0).
  1181  func (t *T) Deadline() (deadline time.Time, ok bool) {
  1182  	deadline = t.context.deadline
  1183  	return deadline, !deadline.IsZero()
  1184  }
  1185  
  1186  // testContext holds all fields that are common to all tests. This includes
  1187  // synchronization primitives to run at most *parallel tests.
  1188  type testContext struct {
  1189  	match    *matcher
  1190  	deadline time.Time
  1191  
  1192  	mu sync.Mutex
  1193  
  1194  	// Channel used to signal tests that are ready to be run in parallel.
  1195  	startParallel chan bool
  1196  
  1197  	// running is the number of tests currently running in parallel.
  1198  	// This does not include tests that are waiting for subtests to complete.
  1199  	running int
  1200  
  1201  	// numWaiting is the number tests waiting to be run in parallel.
  1202  	numWaiting int
  1203  
  1204  	// maxParallel is a copy of the parallel flag.
  1205  	maxParallel int
  1206  }
  1207  
  1208  func newTestContext(maxParallel int, m *matcher) *testContext {
  1209  	return &testContext{
  1210  		match:         m,
  1211  		startParallel: make(chan bool),
  1212  		maxParallel:   maxParallel,
  1213  		running:       1, // Set the count to 1 for the main (sequential) test.
  1214  	}
  1215  }
  1216  
  1217  func (c *testContext) waitParallel() {
  1218  	c.mu.Lock()
  1219  	if c.running < c.maxParallel {
  1220  		c.running++
  1221  		c.mu.Unlock()
  1222  		return
  1223  	}
  1224  	c.numWaiting++
  1225  	c.mu.Unlock()
  1226  	<-c.startParallel
  1227  }
  1228  
  1229  func (c *testContext) release() {
  1230  	c.mu.Lock()
  1231  	if c.numWaiting == 0 {
  1232  		c.running--
  1233  		c.mu.Unlock()
  1234  		return
  1235  	}
  1236  	c.numWaiting--
  1237  	c.mu.Unlock()
  1238  	c.startParallel <- true // Pick a waiting test to be run.
  1239  }
  1240  
  1241  // No one should be using func Main anymore.
  1242  // See the doc comment on func Main and use MainStart instead.
  1243  var errMain = errors.New("testing: unexpected use of func Main")
  1244  
  1245  type matchStringOnly func(pat, str string) (bool, error)
  1246  
  1247  func (f matchStringOnly) MatchString(pat, str string) (bool, error)   { return f(pat, str) }
  1248  func (f matchStringOnly) StartCPUProfile(w io.Writer) error           { return errMain }
  1249  func (f matchStringOnly) StopCPUProfile()                             {}
  1250  func (f matchStringOnly) WriteProfileTo(string, io.Writer, int) error { return errMain }
  1251  func (f matchStringOnly) ImportPath() string                          { return "" }
  1252  func (f matchStringOnly) StartTestLog(io.Writer)                      {}
  1253  func (f matchStringOnly) StopTestLog() error                          { return errMain }
  1254  
  1255  // Main is an internal function, part of the implementation of the "go test" command.
  1256  // It was exported because it is cross-package and predates "internal" packages.
  1257  // It is no longer used by "go test" but preserved, as much as possible, for other
  1258  // systems that simulate "go test" using Main, but Main sometimes cannot be updated as
  1259  // new functionality is added to the testing package.
  1260  // Systems simulating "go test" should be updated to use MainStart.
  1261  func Main(matchString func(pat, str string) (bool, error), tests []InternalTest, benchmarks []InternalBenchmark, examples []InternalExample) {
  1262  	os.Exit(MainStart(matchStringOnly(matchString), tests, benchmarks, examples).Run())
  1263  }
  1264  
  1265  // M is a type passed to a TestMain function to run the actual tests.
  1266  type M struct {
  1267  	deps       testDeps
  1268  	tests      []InternalTest
  1269  	benchmarks []InternalBenchmark
  1270  	examples   []InternalExample
  1271  
  1272  	timer     *time.Timer
  1273  	afterOnce sync.Once
  1274  
  1275  	numRun int
  1276  
  1277  	// value to pass to os.Exit, the outer test func main
  1278  	// harness calls os.Exit with this code. See #34129.
  1279  	exitCode int
  1280  }
  1281  
  1282  // testDeps is an internal interface of functionality that is
  1283  // passed into this package by a test's generated main package.
  1284  // The canonical implementation of this interface is
  1285  // testing/internal/testdeps's TestDeps.
  1286  type testDeps interface {
  1287  	ImportPath() string
  1288  	MatchString(pat, str string) (bool, error)
  1289  	StartCPUProfile(io.Writer) error
  1290  	StopCPUProfile()
  1291  	StartTestLog(io.Writer)
  1292  	StopTestLog() error
  1293  	WriteProfileTo(string, io.Writer, int) error
  1294  }
  1295  
  1296  // MainStart is meant for use by tests generated by 'go test'.
  1297  // It is not meant to be called directly and is not subject to the Go 1 compatibility document.
  1298  // It may change signature from release to release.
  1299  func MainStart(deps testDeps, tests []InternalTest, benchmarks []InternalBenchmark, examples []InternalExample) *M {
  1300  	Init()
  1301  	return &M{
  1302  		deps:       deps,
  1303  		tests:      tests,
  1304  		benchmarks: benchmarks,
  1305  		examples:   examples,
  1306  	}
  1307  }
  1308  
  1309  // Run runs the tests. It returns an exit code to pass to os.Exit.
  1310  func (m *M) Run() (code int) {
  1311  	defer func() {
  1312  		code = m.exitCode
  1313  	}()
  1314  
  1315  	// Count the number of calls to m.Run.
  1316  	// We only ever expected 1, but we didn't enforce that,
  1317  	// and now there are tests in the wild that call m.Run multiple times.
  1318  	// Sigh. golang.org/issue/23129.
  1319  	m.numRun++
  1320  
  1321  	// TestMain may have already called flag.Parse.
  1322  	if !flag.Parsed() {
  1323  		flag.Parse()
  1324  	}
  1325  
  1326  	if *parallel < 1 {
  1327  		fmt.Fprintln(os.Stderr, "testing: -parallel can only be given a positive integer")
  1328  		flag.Usage()
  1329  		m.exitCode = 2
  1330  		return
  1331  	}
  1332  
  1333  	if len(*matchList) != 0 {
  1334  		listTests(m.deps.MatchString, m.tests, m.benchmarks, m.examples)
  1335  		m.exitCode = 0
  1336  		return
  1337  	}
  1338  
  1339  	parseCpuList()
  1340  
  1341  	m.before()
  1342  	defer m.after()
  1343  	deadline := m.startAlarm()
  1344  	haveExamples = len(m.examples) > 0
  1345  	testRan, testOk := runTests(m.deps.MatchString, m.tests, deadline)
  1346  	exampleRan, exampleOk := runExamples(m.deps.MatchString, m.examples)
  1347  	m.stopAlarm()
  1348  	if !testRan && !exampleRan && *matchBenchmarks == "" {
  1349  		fmt.Fprintln(os.Stderr, "testing: warning: no tests to run")
  1350  	}
  1351  	if !testOk || !exampleOk || !runBenchmarks(m.deps.ImportPath(), m.deps.MatchString, m.benchmarks) || race.Errors() > 0 {
  1352  		fmt.Println("FAIL")
  1353  		m.exitCode = 1
  1354  		return
  1355  	}
  1356  
  1357  	fmt.Println("PASS")
  1358  	m.exitCode = 0
  1359  	return
  1360  }
  1361  
  1362  func (t *T) report() {
  1363  	if t.parent == nil {
  1364  		return
  1365  	}
  1366  	dstr := fmtDuration(t.duration)
  1367  	format := "--- %s: %s (%s)\n"
  1368  	if t.Failed() {
  1369  		t.flushToParent(t.name, format, "FAIL", t.name, dstr)
  1370  	} else if t.chatty != nil {
  1371  		if t.Skipped() {
  1372  			t.flushToParent(t.name, format, "SKIP", t.name, dstr)
  1373  		} else {
  1374  			t.flushToParent(t.name, format, "PASS", t.name, dstr)
  1375  		}
  1376  	}
  1377  }
  1378  
  1379  func listTests(matchString func(pat, str string) (bool, error), tests []InternalTest, benchmarks []InternalBenchmark, examples []InternalExample) {
  1380  	if _, err := matchString(*matchList, "non-empty"); err != nil {
  1381  		fmt.Fprintf(os.Stderr, "testing: invalid regexp in -test.list (%q): %s\n", *matchList, err)
  1382  		os.Exit(1)
  1383  	}
  1384  
  1385  	for _, test := range tests {
  1386  		if ok, _ := matchString(*matchList, test.Name); ok {
  1387  			fmt.Println(test.Name)
  1388  		}
  1389  	}
  1390  	for _, bench := range benchmarks {
  1391  		if ok, _ := matchString(*matchList, bench.Name); ok {
  1392  			fmt.Println(bench.Name)
  1393  		}
  1394  	}
  1395  	for _, example := range examples {
  1396  		if ok, _ := matchString(*matchList, example.Name); ok {
  1397  			fmt.Println(example.Name)
  1398  		}
  1399  	}
  1400  }
  1401  
  1402  // RunTests is an internal function but exported because it is cross-package;
  1403  // it is part of the implementation of the "go test" command.
  1404  func RunTests(matchString func(pat, str string) (bool, error), tests []InternalTest) (ok bool) {
  1405  	var deadline time.Time
  1406  	if *timeout > 0 {
  1407  		deadline = time.Now().Add(*timeout)
  1408  	}
  1409  	ran, ok := runTests(matchString, tests, deadline)
  1410  	if !ran && !haveExamples {
  1411  		fmt.Fprintln(os.Stderr, "testing: warning: no tests to run")
  1412  	}
  1413  	return ok
  1414  }
  1415  
  1416  func runTests(matchString func(pat, str string) (bool, error), tests []InternalTest, deadline time.Time) (ran, ok bool) {
  1417  	ok = true
  1418  	for _, procs := range cpuList {
  1419  		runtime.GOMAXPROCS(procs)
  1420  		for i := uint(0); i < *count; i++ {
  1421  			if shouldFailFast() {
  1422  				break
  1423  			}
  1424  			ctx := newTestContext(*parallel, newMatcher(matchString, *match, "-test.run"))
  1425  			ctx.deadline = deadline
  1426  			t := &T{
  1427  				common: common{
  1428  					signal:  make(chan bool),
  1429  					barrier: make(chan bool),
  1430  					w:       os.Stdout,
  1431  				},
  1432  				context: ctx,
  1433  			}
  1434  			if Verbose() {
  1435  				t.chatty = newChattyPrinter(t.w)
  1436  			}
  1437  			tRunner(t, func(t *T) {
  1438  				for _, test := range tests {
  1439  					t.Run(test.Name, test.F)
  1440  				}
  1441  				// Run catching the signal rather than the tRunner as a separate
  1442  				// goroutine to avoid adding a goroutine during the sequential
  1443  				// phase as this pollutes the stacktrace output when aborting.
  1444  				go func() { <-t.signal }()
  1445  			})
  1446  			ok = ok && !t.Failed()
  1447  			ran = ran || t.ran
  1448  		}
  1449  	}
  1450  	return ran, ok
  1451  }
  1452  
  1453  // before runs before all testing.
  1454  func (m *M) before() {
  1455  	if *memProfileRate > 0 {
  1456  		runtime.MemProfileRate = *memProfileRate
  1457  	}
  1458  	if *cpuProfile != "" {
  1459  		f, err := os.Create(toOutputDir(*cpuProfile))
  1460  		if err != nil {
  1461  			fmt.Fprintf(os.Stderr, "testing: %s\n", err)
  1462  			return
  1463  		}
  1464  		if err := m.deps.StartCPUProfile(f); err != nil {
  1465  			fmt.Fprintf(os.Stderr, "testing: can't start cpu profile: %s\n", err)
  1466  			f.Close()
  1467  			return
  1468  		}
  1469  		// Could save f so after can call f.Close; not worth the effort.
  1470  	}
  1471  	if *traceFile != "" {
  1472  		f, err := os.Create(toOutputDir(*traceFile))
  1473  		if err != nil {
  1474  			fmt.Fprintf(os.Stderr, "testing: %s\n", err)
  1475  			return
  1476  		}
  1477  		if err := trace.Start(f); err != nil {
  1478  			fmt.Fprintf(os.Stderr, "testing: can't start tracing: %s\n", err)
  1479  			f.Close()
  1480  			return
  1481  		}
  1482  		// Could save f so after can call f.Close; not worth the effort.
  1483  	}
  1484  	if *blockProfile != "" && *blockProfileRate >= 0 {
  1485  		runtime.SetBlockProfileRate(*blockProfileRate)
  1486  	}
  1487  	if *mutexProfile != "" && *mutexProfileFraction >= 0 {
  1488  		runtime.SetMutexProfileFraction(*mutexProfileFraction)
  1489  	}
  1490  	if *coverProfile != "" && cover.Mode == "" {
  1491  		fmt.Fprintf(os.Stderr, "testing: cannot use -test.coverprofile because test binary was not built with coverage enabled\n")
  1492  		os.Exit(2)
  1493  	}
  1494  	if *testlog != "" {
  1495  		// Note: Not using toOutputDir.
  1496  		// This file is for use by cmd/go, not users.
  1497  		var f *os.File
  1498  		var err error
  1499  		if m.numRun == 1 {
  1500  			f, err = os.Create(*testlog)
  1501  		} else {
  1502  			f, err = os.OpenFile(*testlog, os.O_WRONLY, 0)
  1503  			if err == nil {
  1504  				f.Seek(0, io.SeekEnd)
  1505  			}
  1506  		}
  1507  		if err != nil {
  1508  			fmt.Fprintf(os.Stderr, "testing: %s\n", err)
  1509  			os.Exit(2)
  1510  		}
  1511  		m.deps.StartTestLog(f)
  1512  		testlogFile = f
  1513  	}
  1514  }
  1515  
  1516  // after runs after all testing.
  1517  func (m *M) after() {
  1518  	m.afterOnce.Do(func() {
  1519  		m.writeProfiles()
  1520  	})
  1521  }
  1522  
  1523  func (m *M) writeProfiles() {
  1524  	if *testlog != "" {
  1525  		if err := m.deps.StopTestLog(); err != nil {
  1526  			fmt.Fprintf(os.Stderr, "testing: can't write %s: %s\n", *testlog, err)
  1527  			os.Exit(2)
  1528  		}
  1529  		if err := testlogFile.Close(); err != nil {
  1530  			fmt.Fprintf(os.Stderr, "testing: can't write %s: %s\n", *testlog, err)
  1531  			os.Exit(2)
  1532  		}
  1533  	}
  1534  	if *cpuProfile != "" {
  1535  		m.deps.StopCPUProfile() // flushes profile to disk
  1536  	}
  1537  	if *traceFile != "" {
  1538  		trace.Stop() // flushes trace to disk
  1539  	}
  1540  	if *memProfile != "" {
  1541  		f, err := os.Create(toOutputDir(*memProfile))
  1542  		if err != nil {
  1543  			fmt.Fprintf(os.Stderr, "testing: %s\n", err)
  1544  			os.Exit(2)
  1545  		}
  1546  		runtime.GC() // materialize all statistics
  1547  		if err = m.deps.WriteProfileTo("allocs", f, 0); err != nil {
  1548  			fmt.Fprintf(os.Stderr, "testing: can't write %s: %s\n", *memProfile, err)
  1549  			os.Exit(2)
  1550  		}
  1551  		f.Close()
  1552  	}
  1553  	if *blockProfile != "" && *blockProfileRate >= 0 {
  1554  		f, err := os.Create(toOutputDir(*blockProfile))
  1555  		if err != nil {
  1556  			fmt.Fprintf(os.Stderr, "testing: %s\n", err)
  1557  			os.Exit(2)
  1558  		}
  1559  		if err = m.deps.WriteProfileTo("block", f, 0); err != nil {
  1560  			fmt.Fprintf(os.Stderr, "testing: can't write %s: %s\n", *blockProfile, err)
  1561  			os.Exit(2)
  1562  		}
  1563  		f.Close()
  1564  	}
  1565  	if *mutexProfile != "" && *mutexProfileFraction >= 0 {
  1566  		f, err := os.Create(toOutputDir(*mutexProfile))
  1567  		if err != nil {
  1568  			fmt.Fprintf(os.Stderr, "testing: %s\n", err)
  1569  			os.Exit(2)
  1570  		}
  1571  		if err = m.deps.WriteProfileTo("mutex", f, 0); err != nil {
  1572  			fmt.Fprintf(os.Stderr, "testing: can't write %s: %s\n", *mutexProfile, err)
  1573  			os.Exit(2)
  1574  		}
  1575  		f.Close()
  1576  	}
  1577  	if cover.Mode != "" {
  1578  		coverReport()
  1579  	}
  1580  }
  1581  
  1582  // toOutputDir returns the file name relocated, if required, to outputDir.
  1583  // Simple implementation to avoid pulling in path/filepath.
  1584  func toOutputDir(path string) string {
  1585  	if *outputDir == "" || path == "" {
  1586  		return path
  1587  	}
  1588  	// On Windows, it's clumsy, but we can be almost always correct
  1589  	// by just looking for a drive letter and a colon.
  1590  	// Absolute paths always have a drive letter (ignoring UNC).
  1591  	// Problem: if path == "C:A" and outputdir == "C:\Go" it's unclear
  1592  	// what to do, but even then path/filepath doesn't help.
  1593  	// TODO: Worth doing better? Probably not, because we're here only
  1594  	// under the management of go test.
  1595  	if runtime.GOOS == "windows" && len(path) >= 2 {
  1596  		letter, colon := path[0], path[1]
  1597  		if ('a' <= letter && letter <= 'z' || 'A' <= letter && letter <= 'Z') && colon == ':' {
  1598  			// If path starts with a drive letter we're stuck with it regardless.
  1599  			return path
  1600  		}
  1601  	}
  1602  	if os.IsPathSeparator(path[0]) {
  1603  		return path
  1604  	}
  1605  	return fmt.Sprintf("%s%c%s", *outputDir, os.PathSeparator, path)
  1606  }
  1607  
  1608  // startAlarm starts an alarm if requested.
  1609  func (m *M) startAlarm() time.Time {
  1610  	if *timeout <= 0 {
  1611  		return time.Time{}
  1612  	}
  1613  
  1614  	deadline := time.Now().Add(*timeout)
  1615  	m.timer = time.AfterFunc(*timeout, func() {
  1616  		m.after()
  1617  		debug.SetTraceback("all")
  1618  		panic(fmt.Sprintf("test timed out after %v", *timeout))
  1619  	})
  1620  	return deadline
  1621  }
  1622  
  1623  // stopAlarm turns off the alarm.
  1624  func (m *M) stopAlarm() {
  1625  	if *timeout > 0 {
  1626  		m.timer.Stop()
  1627  	}
  1628  }
  1629  
  1630  func parseCpuList() {
  1631  	for _, val := range strings.Split(*cpuListStr, ",") {
  1632  		val = strings.TrimSpace(val)
  1633  		if val == "" {
  1634  			continue
  1635  		}
  1636  		cpu, err := strconv.Atoi(val)
  1637  		if err != nil || cpu <= 0 {
  1638  			fmt.Fprintf(os.Stderr, "testing: invalid value %q for -test.cpu\n", val)
  1639  			os.Exit(1)
  1640  		}
  1641  		cpuList = append(cpuList, cpu)
  1642  	}
  1643  	if cpuList == nil {
  1644  		cpuList = append(cpuList, runtime.GOMAXPROCS(-1))
  1645  	}
  1646  }
  1647  
  1648  func shouldFailFast() bool {
  1649  	return *failFast && atomic.LoadUint32(&numFailed) > 0
  1650  }
  1651  

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