// Copyright 2009 The Go Authors. All rights reserved. // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. // Package testing provides support for automated testing of Go packages. // It is intended to be used in concert with the ``go test'' command, which automates // execution of any function of the form // func TestXxx(*testing.T) // where Xxx does not start with a lowercase letter. The function name // serves to identify the test routine. // // Within these functions, use the Error, Fail or related methods to signal failure. // // To write a new test suite, create a file whose name ends _test.go that // contains the TestXxx functions as described here. Put the file in the same // package as the one being tested. The file will be excluded from regular // package builds but will be included when the ``go test'' command is run. // For more detail, run ``go help test'' and ``go help testflag''. // // Tests and benchmarks may be skipped if not applicable with a call to // the Skip method of *T and *B: // func TestTimeConsuming(t *testing.T) { // if testing.Short() { // t.Skip("skipping test in short mode.") // } // ... // } // // Benchmarks // // Functions of the form // func BenchmarkXxx(*testing.B) // are considered benchmarks, and are executed by the "go test" command when // its -bench flag is provided. Benchmarks are run sequentially. // // For a description of the testing flags, see // https://golang.org/cmd/go/#hdr-Testing_flags // // A sample benchmark function looks like this: // func BenchmarkHello(b *testing.B) { // for i := 0; i < b.N; i++ { // fmt.Sprintf("hello") // } // } // // The benchmark function must run the target code b.N times. // During benchmark execution, b.N is adjusted until the benchmark function lasts // long enough to be timed reliably. The output // BenchmarkHello 10000000 282 ns/op // means that the loop ran 10000000 times at a speed of 282 ns per loop. // // If a benchmark needs some expensive setup before running, the timer // may be reset: // // func BenchmarkBigLen(b *testing.B) { // big := NewBig() // b.ResetTimer() // for i := 0; i < b.N; i++ { // big.Len() // } // } // // If a benchmark needs to test performance in a parallel setting, it may use // the RunParallel helper function; such benchmarks are intended to be used with // the go test -cpu flag: // // func BenchmarkTemplateParallel(b *testing.B) { // templ := template.Must(template.New("test").Parse("Hello, {{.}}!")) // b.RunParallel(func(pb *testing.PB) { // var buf bytes.Buffer // for pb.Next() { // buf.Reset() // templ.Execute(&buf, "World") // } // }) // } // // Examples // // The package also runs and verifies example code. Example functions may // include a concluding line comment that begins with "Output:" and is compared with // the standard output of the function when the tests are run. (The comparison // ignores leading and trailing space.) These are examples of an example: // // func ExampleHello() { // fmt.Println("hello") // // Output: hello // } // // func ExampleSalutations() { // fmt.Println("hello, and") // fmt.Println("goodbye") // // Output: // // hello, and // // goodbye // } // // The comment prefix "Unordered output:" is like "Output:", but matches any // line order: // // func ExamplePerm() { // for _, value := range Perm(4) { // fmt.Println(value) // } // // Unordered output: 4 // // 2 // // 1 // // 3 // // 0 // } // // Example functions without output comments are compiled but not executed. // // The naming convention to declare examples for the package, a function F, a type T and // method M on type T are: // // func Example() { ... } // func ExampleF() { ... } // func ExampleT() { ... } // func ExampleT_M() { ... } // // Multiple example functions for a package/type/function/method may be provided by // appending a distinct suffix to the name. The suffix must start with a // lower-case letter. // // func Example_suffix() { ... } // func ExampleF_suffix() { ... } // func ExampleT_suffix() { ... } // func ExampleT_M_suffix() { ... } // // The entire test file is presented as the example when it contains a single // example function, at least one other function, type, variable, or constant // declaration, and no test or benchmark functions. // // Subtests and Sub-benchmarks // // The Run methods of T and B allow defining subtests and sub-benchmarks, // without having to define separate functions for each. This enables uses // like table-driven benchmarks and creating hierarchical tests. // It also provides a way to share common setup and tear-down code: // // func TestFoo(t *testing.T) { // // <setup code> // t.Run("A=1", func(t *testing.T) { ... }) // t.Run("A=2", func(t *testing.T) { ... }) // t.Run("B=1", func(t *testing.T) { ... }) // // <tear-down code> // } // // Each subtest and sub-benchmark has a unique name: the combination of the name // of the top-level test and the sequence of names passed to Run, separated by // slashes, with an optional trailing sequence number for disambiguation. // // The argument to the -run and -bench command-line flags is an unanchored regular // expression that matches the test's name. For tests with multiple slash-separated // elements, such as subtests, the argument is itself slash-separated, with // expressions matching each name element in turn. Because it is unanchored, an // empty expression matches any string. // For example, using "matching" to mean "whose name contains": // // go test -run '' # Run all tests. // go test -run Foo # Run top-level tests matching "Foo", such as "TestFooBar". // go test -run Foo/A= # For top-level tests matching "Foo", run subtests matching "A=". // go test -run /A=1 # For all top-level tests, run subtests matching "A=1". // // Subtests can also be used to control parallelism. A parent test will only // complete once all of its subtests complete. In this example, all tests are // run in parallel with each other, and only with each other, regardless of // other top-level tests that may be defined: // // func TestGroupedParallel(t *testing.T) { // for _, tc := range tests { // tc := tc // capture range variable // t.Run(tc.Name, func(t *testing.T) { // t.Parallel() // ... // }) // } // } // // The race detector kills the program if it exceeds 8192 concurrent goroutines, // so use care when running parallel tests with the -race flag set. // // Run does not return until parallel subtests have completed, providing a way // to clean up after a group of parallel tests: // // func TestTeardownParallel(t *testing.T) { // // This Run will not return until the parallel tests finish. // t.Run("group", func(t *testing.T) { // t.Run("Test1", parallelTest1) // t.Run("Test2", parallelTest2) // t.Run("Test3", parallelTest3) // }) // // <tear-down code> // } // // Main // // It is sometimes necessary for a test program to do extra setup or teardown // before or after testing. It is also sometimes necessary for a test to control // which code runs on the main thread. To support these and other cases, // if a test file contains a function: // // func TestMain(m *testing.M) // // then the generated test will call TestMain(m) instead of running the tests // directly. TestMain runs in the main goroutine and can do whatever setup // and teardown is necessary around a call to m.Run. It should then call // os.Exit with the result of m.Run. When TestMain is called, flag.Parse has // not been run. If TestMain depends on command-line flags, including those // of the testing package, it should call flag.Parse explicitly. // // A simple implementation of TestMain is: // // func TestMain(m *testing.M) { // // call flag.Parse() here if TestMain uses flags // os.Exit(m.Run()) // } // package testing import ( "bytes" "errors" "flag" "fmt" "internal/race" "io" "os" "runtime" "runtime/debug" "runtime/trace" "strconv" "strings" "sync" "sync/atomic" "time" ) var ( // The short flag requests that tests run more quickly, but its functionality // is provided by test writers themselves. The testing package is just its // home. The all.bash installation script sets it to make installation more // efficient, but by default the flag is off so a plain "go test" will do a // full test of the package. short = flag.Bool("test.short", false, "run smaller test suite to save time") // The failfast flag requests that test execution stop after the first test failure. failFast = flag.Bool("test.failfast", false, "do not start new tests after the first test failure") // The directory in which to create profile files and the like. When run from // "go test", the binary always runs in the source directory for the package; // this flag lets "go test" tell the binary to write the files in the directory where // the "go test" command is run. outputDir = flag.String("test.outputdir", "", "write profiles to `dir`") // Report as tests are run; default is silent for success. chatty = flag.Bool("test.v", false, "verbose: print additional output") count = flag.Uint("test.count", 1, "run tests and benchmarks `n` times") coverProfile = flag.String("test.coverprofile", "", "write a coverage profile to `file`") matchList = flag.String("test.list", "", "list tests, examples, and benchmarks matching `regexp` then exit") match = flag.String("test.run", "", "run only tests and examples matching `regexp`") memProfile = flag.String("test.memprofile", "", "write an allocation profile to `file`") memProfileRate = flag.Int("test.memprofilerate", 0, "set memory allocation profiling `rate` (see runtime.MemProfileRate)") cpuProfile = flag.String("test.cpuprofile", "", "write a cpu profile to `file`") blockProfile = flag.String("test.blockprofile", "", "write a goroutine blocking profile to `file`") blockProfileRate = flag.Int("test.blockprofilerate", 1, "set blocking profile `rate` (see runtime.SetBlockProfileRate)") mutexProfile = flag.String("test.mutexprofile", "", "write a mutex contention profile to the named file after execution") mutexProfileFraction = flag.Int("test.mutexprofilefraction", 1, "if >= 0, calls runtime.SetMutexProfileFraction()") traceFile = flag.String("test.trace", "", "write an execution trace to `file`") timeout = flag.Duration("test.timeout", 0, "panic test binary after duration `d` (default 0, timeout disabled)") cpuListStr = flag.String("test.cpu", "", "comma-separated `list` of cpu counts to run each test with") parallel = flag.Int("test.parallel", runtime.GOMAXPROCS(0), "run at most `n` tests in parallel") testlog = flag.String("test.testlogfile", "", "write test action log to `file` (for use only by cmd/go)") haveExamples bool // are there examples? cpuList []int testlogFile *os.File numFailed uint32 // number of test failures ) // The maximum number of stack frames to go through when skipping helper functions for // the purpose of decorating log messages. const maxStackLen = 50 // common holds the elements common between T and B and // captures common methods such as Errorf. type common struct { mu sync.RWMutex // guards this group of fields output []byte // Output generated by test or benchmark. w io.Writer // For flushToParent. ran bool // Test or benchmark (or one of its subtests) was executed. failed bool // Test or benchmark has failed. skipped bool // Test of benchmark has been skipped. done bool // Test is finished and all subtests have completed. helpers map[string]struct{} // functions to be skipped when writing file/line info chatty bool // A copy of the chatty flag. finished bool // Test function has completed. hasSub int32 // written atomically raceErrors int // number of races detected during test runner string // function name of tRunner running the test parent *common level int // Nesting depth of test or benchmark. creator []uintptr // If level > 0, the stack trace at the point where the parent called t.Run. name string // Name of test or benchmark. start time.Time // Time test or benchmark started duration time.Duration barrier chan bool // To signal parallel subtests they may start. signal chan bool // To signal a test is done. sub []*T // Queue of subtests to be run in parallel. } // Short reports whether the -test.short flag is set. func Short() bool { return *short } // CoverMode reports what the test coverage mode is set to. The // values are "set", "count", or "atomic". The return value will be // empty if test coverage is not enabled. func CoverMode() string { return cover.Mode } // Verbose reports whether the -test.v flag is set. func Verbose() bool { return *chatty } // frameSkip searches, starting after skip frames, for the first caller frame // in a function not marked as a helper and returns that frame. // The search stops if it finds a tRunner function that // was the entry point into the test and the test is not a subtest. // This function must be called with c.mu held. func (c *common) frameSkip(skip int) runtime.Frame { // If the search continues into the parent test, we'll have to hold // its mu temporarily. If we then return, we need to unlock it. shouldUnlock := false defer func() { if shouldUnlock { c.mu.Unlock() } }() var pc [maxStackLen]uintptr // Skip two extra frames to account for this function // and runtime.Callers itself. n := runtime.Callers(skip+2, pc[:]) if n == 0 { panic("testing: zero callers found") } frames := runtime.CallersFrames(pc[:n]) var firstFrame, prevFrame, frame runtime.Frame for more := true; more; prevFrame = frame { frame, more = frames.Next() if firstFrame.PC == 0 { firstFrame = frame } if frame.Function == c.runner { // We've gone up all the way to the tRunner calling // the test function (so the user must have // called tb.Helper from inside that test function). // If this is a top-level test, only skip up to the test function itself. // If we're in a subtest, continue searching in the parent test, // starting from the point of the call to Run which created this subtest. if c.level > 1 { frames = runtime.CallersFrames(c.creator) parent := c.parent // We're no longer looking at the current c after this point, // so we should unlock its mu, unless it's the original receiver, // in which case our caller doesn't expect us to do that. if shouldUnlock { c.mu.Unlock() } c = parent // Remember to unlock c.mu when we no longer need it, either // because we went up another nesting level, or because we // returned. shouldUnlock = true c.mu.Lock() continue } return prevFrame } if _, ok := c.helpers[frame.Function]; !ok { // Found a frame that wasn't inside a helper function. return frame } } return firstFrame } // decorate prefixes the string with the file and line of the call site // and inserts the final newline if needed and indentation spaces for formatting. // This function must be called with c.mu held. func (c *common) decorate(s string) string { frame := c.frameSkip(3) // decorate + log + public function. file := frame.File line := frame.Line if file != "" { // Truncate file name at last file name separator. if index := strings.LastIndex(file, "/"); index >= 0 { file = file[index+1:] } else if index = strings.LastIndex(file, "\\"); index >= 0 { file = file[index+1:] } } else { file = "???" } if line == 0 { line = 1 } buf := new(strings.Builder) // Every line is indented at least 4 spaces. buf.WriteString(" ") fmt.Fprintf(buf, "%s:%d: ", file, line) lines := strings.Split(s, "\n") if l := len(lines); l > 1 && lines[l-1] == "" { lines = lines[:l-1] } for i, line := range lines { if i > 0 { // Second and subsequent lines are indented an additional 4 spaces. buf.WriteString("\n ") } buf.WriteString(line) } buf.WriteByte('\n') return buf.String() } // flushToParent writes c.output to the parent after first writing the header // with the given format and arguments. func (c *common) flushToParent(format string, args ...interface{}) { p := c.parent p.mu.Lock() defer p.mu.Unlock() fmt.Fprintf(p.w, format, args...) c.mu.Lock() defer c.mu.Unlock() io.Copy(p.w, bytes.NewReader(c.output)) c.output = c.output[:0] } type indenter struct { c *common } func (w indenter) Write(b []byte) (n int, err error) { n = len(b) for len(b) > 0 { end := bytes.IndexByte(b, '\n') if end == -1 { end = len(b) } else { end++ } // An indent of 4 spaces will neatly align the dashes with the status // indicator of the parent. const indent = " " w.c.output = append(w.c.output, indent...) w.c.output = append(w.c.output, b[:end]...) b = b[end:] } return } // fmtDuration returns a string representing d in the form "87.00s". func fmtDuration(d time.Duration) string { return fmt.Sprintf("%.2fs", d.Seconds()) } // TB is the interface common to T and B. type TB interface { Error(args ...interface{}) Errorf(format string, args ...interface{}) Fail() FailNow() Failed() bool Fatal(args ...interface{}) Fatalf(format string, args ...interface{}) Log(args ...interface{}) Logf(format string, args ...interface{}) Name() string Skip(args ...interface{}) SkipNow() Skipf(format string, args ...interface{}) Skipped() bool Helper() // A private method to prevent users implementing the // interface and so future additions to it will not // violate Go 1 compatibility. private() } var _ TB = (*T)(nil) var _ TB = (*B)(nil) // T is a type passed to Test functions to manage test state and support formatted test logs. // Logs are accumulated during execution and dumped to standard output when done. // // A test ends when its Test function returns or calls any of the methods // FailNow, Fatal, Fatalf, SkipNow, Skip, or Skipf. Those methods, as well as // the Parallel method, must be called only from the goroutine running the // Test function. // // The other reporting methods, such as the variations of Log and Error, // may be called simultaneously from multiple goroutines. type T struct { common isParallel bool context *testContext // For running tests and subtests. } func (c *common) private() {} // Name returns the name of the running test or benchmark. func (c *common) Name() string { return c.name } func (c *common) setRan() { if c.parent != nil { c.parent.setRan() } c.mu.Lock() defer c.mu.Unlock() c.ran = true } // Fail marks the function as having failed but continues execution. func (c *common) Fail() { if c.parent != nil { c.parent.Fail() } c.mu.Lock() defer c.mu.Unlock() // c.done needs to be locked to synchronize checks to c.done in parent tests. if c.done { panic("Fail in goroutine after " + c.name + " has completed") } c.failed = true } // Failed reports whether the function has failed. func (c *common) Failed() bool { c.mu.RLock() failed := c.failed c.mu.RUnlock() return failed || c.raceErrors+race.Errors() > 0 } // FailNow marks the function as having failed and stops its execution // by calling runtime.Goexit (which then runs all deferred calls in the // current goroutine). // Execution will continue at the next test or benchmark. // FailNow must be called from the goroutine running the // test or benchmark function, not from other goroutines // created during the test. Calling FailNow does not stop // those other goroutines. func (c *common) FailNow() { c.Fail() // Calling runtime.Goexit will exit the goroutine, which // will run the deferred functions in this goroutine, // which will eventually run the deferred lines in tRunner, // which will signal to the test loop that this test is done. // // A previous version of this code said: // // c.duration = ... // c.signal <- c.self // runtime.Goexit() // // This previous version duplicated code (those lines are in // tRunner no matter what), but worse the goroutine teardown // implicit in runtime.Goexit was not guaranteed to complete // before the test exited. If a test deferred an important cleanup // function (like removing temporary files), there was no guarantee // it would run on a test failure. Because we send on c.signal during // a top-of-stack deferred function now, we know that the send // only happens after any other stacked defers have completed. c.finished = true runtime.Goexit() } // log generates the output. It's always at the same stack depth. func (c *common) log(s string) { c.mu.Lock() defer c.mu.Unlock() c.output = append(c.output, c.decorate(s)...) } // Log formats its arguments using default formatting, analogous to Println, // and records the text in the error log. For tests, the text will be printed only if // the test fails or the -test.v flag is set. For benchmarks, the text is always // printed to avoid having performance depend on the value of the -test.v flag. func (c *common) Log(args ...interface{}) { c.log(fmt.Sprintln(args...)) } // Logf formats its arguments according to the format, analogous to Printf, and // records the text in the error log. A final newline is added if not provided. For // tests, the text will be printed only if the test fails or the -test.v flag is // set. For benchmarks, the text is always printed to avoid having performance // depend on the value of the -test.v flag. func (c *common) Logf(format string, args ...interface{}) { c.log(fmt.Sprintf(format, args...)) } // Error is equivalent to Log followed by Fail. func (c *common) Error(args ...interface{}) { c.log(fmt.Sprintln(args...)) c.Fail() } // Errorf is equivalent to Logf followed by Fail. func (c *common) Errorf(format string, args ...interface{}) { c.log(fmt.Sprintf(format, args...)) c.Fail() } // Fatal is equivalent to Log followed by FailNow. func (c *common) Fatal(args ...interface{}) { c.log(fmt.Sprintln(args...)) c.FailNow() } // Fatalf is equivalent to Logf followed by FailNow. func (c *common) Fatalf(format string, args ...interface{}) { c.log(fmt.Sprintf(format, args...)) c.FailNow() } // Skip is equivalent to Log followed by SkipNow. func (c *common) Skip(args ...interface{}) { c.log(fmt.Sprintln(args...)) c.SkipNow() } // Skipf is equivalent to Logf followed by SkipNow. func (c *common) Skipf(format string, args ...interface{}) { c.log(fmt.Sprintf(format, args...)) c.SkipNow() } // SkipNow marks the test as having been skipped and stops its execution // by calling runtime.Goexit. // If a test fails (see Error, Errorf, Fail) and is then skipped, // it is still considered to have failed. // Execution will continue at the next test or benchmark. See also FailNow. // SkipNow must be called from the goroutine running the test, not from // other goroutines created during the test. Calling SkipNow does not stop // those other goroutines. func (c *common) SkipNow() { c.skip() c.finished = true runtime.Goexit() } func (c *common) skip() { c.mu.Lock() defer c.mu.Unlock() c.skipped = true } // Skipped reports whether the test was skipped. func (c *common) Skipped() bool { c.mu.RLock() defer c.mu.RUnlock() return c.skipped } // Helper marks the calling function as a test helper function. // When printing file and line information, that function will be skipped. // Helper may be called simultaneously from multiple goroutines. func (c *common) Helper() { c.mu.Lock() defer c.mu.Unlock() if c.helpers == nil { c.helpers = make(map[string]struct{}) } c.helpers[callerName(1)] = struct{}{} } // callerName gives the function name (qualified with a package path) // for the caller after skip frames (where 0 means the current function). func callerName(skip int) string { // Make room for the skip PC. var pc [2]uintptr n := runtime.Callers(skip+2, pc[:]) // skip + runtime.Callers + callerName if n == 0 { panic("testing: zero callers found") } frames := runtime.CallersFrames(pc[:n]) frame, _ := frames.Next() return frame.Function } // Parallel signals that this test is to be run in parallel with (and only with) // other parallel tests. When a test is run multiple times due to use of // -test.count or -test.cpu, multiple instances of a single test never run in // parallel with each other. func (t *T) Parallel() { if t.isParallel { panic("testing: t.Parallel called multiple times") } t.isParallel = true // We don't want to include the time we spend waiting for serial tests // in the test duration. Record the elapsed time thus far and reset the // timer afterwards. t.duration += time.Since(t.start) // Add to the list of tests to be released by the parent. t.parent.sub = append(t.parent.sub, t) t.raceErrors += race.Errors() if t.chatty { // Print directly to root's io.Writer so there is no delay. root := t.parent for ; root.parent != nil; root = root.parent { } root.mu.Lock() fmt.Fprintf(root.w, "=== PAUSE %s\n", t.name) root.mu.Unlock() } t.signal <- true // Release calling test. <-t.parent.barrier // Wait for the parent test to complete. t.context.waitParallel() if t.chatty { // Print directly to root's io.Writer so there is no delay. root := t.parent for ; root.parent != nil; root = root.parent { } root.mu.Lock() fmt.Fprintf(root.w, "=== CONT %s\n", t.name) root.mu.Unlock() } t.start = time.Now() t.raceErrors += -race.Errors() } // An internal type but exported because it is cross-package; part of the implementation // of the "go test" command. type InternalTest struct { Name string F func(*T) } var errNilPanicOrGoexit = errors.New("test executed panic(nil) or runtime.Goexit") func tRunner(t *T, fn func(t *T)) { t.runner = callerName(0) // When this goroutine is done, either because fn(t) // returned normally or because a test failure triggered // a call to runtime.Goexit, record the duration and send // a signal saying that the test is done. defer func() { if t.Failed() { atomic.AddUint32(&numFailed, 1) } if t.raceErrors+race.Errors() > 0 { t.Errorf("race detected during execution of test") } t.duration += time.Since(t.start) // If the test panicked, print any test output before dying. err := recover() signal := true if !t.finished && err == nil { err = errNilPanicOrGoexit for p := t.parent; p != nil; p = p.parent { if p.finished { t.Errorf("%v: subtest may have called FailNow on a parent test", err) err = nil signal = false break } } } if err != nil { t.Fail() t.report() panic(err) } if len(t.sub) > 0 { // Run parallel subtests. // Decrease the running count for this test. t.context.release() // Release the parallel subtests. close(t.barrier) // Wait for subtests to complete. for _, sub := range t.sub { <-sub.signal } if !t.isParallel { // Reacquire the count for sequential tests. See comment in Run. t.context.waitParallel() } } else if t.isParallel { // Only release the count for this test if it was run as a parallel // test. See comment in Run method. t.context.release() } t.report() // Report after all subtests have finished. // Do not lock t.done to allow race detector to detect race in case // the user does not appropriately synchronizes a goroutine. t.done = true if t.parent != nil && atomic.LoadInt32(&t.hasSub) == 0 { t.setRan() } t.signal <- signal }() t.start = time.Now() t.raceErrors = -race.Errors() fn(t) // code beyond here will not be executed when FailNow is invoked t.finished = true } // Run runs f as a subtest of t called name. It runs f in a separate goroutine // and blocks until f returns or calls t.Parallel to become a parallel test. // Run reports whether f succeeded (or at least did not fail before calling t.Parallel). // // Run may be called simultaneously from multiple goroutines, but all such calls // must return before the outer test function for t returns. func (t *T) Run(name string, f func(t *T)) bool { atomic.StoreInt32(&t.hasSub, 1) testName, ok, _ := t.context.match.fullName(&t.common, name) if !ok || shouldFailFast() { return true } // Record the stack trace at the point of this call so that if the subtest // function - which runs in a separate stack - is marked as a helper, we can // continue walking the stack into the parent test. var pc [maxStackLen]uintptr n := runtime.Callers(2, pc[:]) t = &T{ common: common{ barrier: make(chan bool), signal: make(chan bool), name: testName, parent: &t.common, level: t.level + 1, creator: pc[:n], chatty: t.chatty, }, context: t.context, } t.w = indenter{&t.common} if t.chatty { // Print directly to root's io.Writer so there is no delay. root := t.parent for ; root.parent != nil; root = root.parent { } root.mu.Lock() fmt.Fprintf(root.w, "=== RUN %s\n", t.name) root.mu.Unlock() } // Instead of reducing the running count of this test before calling the // tRunner and increasing it afterwards, we rely on tRunner keeping the // count correct. This ensures that a sequence of sequential tests runs // without being preempted, even when their parent is a parallel test. This // may especially reduce surprises if *parallel == 1. go tRunner(t, f) if !<-t.signal { // At this point, it is likely that FailNow was called on one of the // parent tests by one of the subtests. Continue aborting up the chain. runtime.Goexit() } return !t.failed } // testContext holds all fields that are common to all tests. This includes // synchronization primitives to run at most *parallel tests. type testContext struct { match *matcher mu sync.Mutex // Channel used to signal tests that are ready to be run in parallel. startParallel chan bool // running is the number of tests currently running in parallel. // This does not include tests that are waiting for subtests to complete. running int // numWaiting is the number tests waiting to be run in parallel. numWaiting int // maxParallel is a copy of the parallel flag. maxParallel int } func newTestContext(maxParallel int, m *matcher) *testContext { return &testContext{ match: m, startParallel: make(chan bool), maxParallel: maxParallel, running: 1, // Set the count to 1 for the main (sequential) test. } } func (c *testContext) waitParallel() { c.mu.Lock() if c.running < c.maxParallel { c.running++ c.mu.Unlock() return } c.numWaiting++ c.mu.Unlock() <-c.startParallel } func (c *testContext) release() { c.mu.Lock() if c.numWaiting == 0 { c.running-- c.mu.Unlock() return } c.numWaiting-- c.mu.Unlock() c.startParallel <- true // Pick a waiting test to be run. } // No one should be using func Main anymore. // See the doc comment on func Main and use MainStart instead. var errMain = errors.New("testing: unexpected use of func Main") type matchStringOnly func(pat, str string) (bool, error) func (f matchStringOnly) MatchString(pat, str string) (bool, error) { return f(pat, str) } func (f matchStringOnly) StartCPUProfile(w io.Writer) error { return errMain } func (f matchStringOnly) StopCPUProfile() {} func (f matchStringOnly) WriteProfileTo(string, io.Writer, int) error { return errMain } func (f matchStringOnly) ImportPath() string { return "" } func (f matchStringOnly) StartTestLog(io.Writer) {} func (f matchStringOnly) StopTestLog() error { return errMain } // Main is an internal function, part of the implementation of the "go test" command. // It was exported because it is cross-package and predates "internal" packages. // It is no longer used by "go test" but preserved, as much as possible, for other // systems that simulate "go test" using Main, but Main sometimes cannot be updated as // new functionality is added to the testing package. // Systems simulating "go test" should be updated to use MainStart. func Main(matchString func(pat, str string) (bool, error), tests []InternalTest, benchmarks []InternalBenchmark, examples []InternalExample) { os.Exit(MainStart(matchStringOnly(matchString), tests, benchmarks, examples).Run()) } // M is a type passed to a TestMain function to run the actual tests. type M struct { deps testDeps tests []InternalTest benchmarks []InternalBenchmark examples []InternalExample timer *time.Timer afterOnce sync.Once numRun int } // testDeps is an internal interface of functionality that is // passed into this package by a test's generated main package. // The canonical implementation of this interface is // testing/internal/testdeps's TestDeps. type testDeps interface { ImportPath() string MatchString(pat, str string) (bool, error) StartCPUProfile(io.Writer) error StopCPUProfile() StartTestLog(io.Writer) StopTestLog() error WriteProfileTo(string, io.Writer, int) error } // MainStart is meant for use by tests generated by 'go test'. // It is not meant to be called directly and is not subject to the Go 1 compatibility document. // It may change signature from release to release. func MainStart(deps testDeps, tests []InternalTest, benchmarks []InternalBenchmark, examples []InternalExample) *M { return &M{ deps: deps, tests: tests, benchmarks: benchmarks, examples: examples, } } // Run runs the tests. It returns an exit code to pass to os.Exit. func (m *M) Run() int { // Count the number of calls to m.Run. // We only ever expected 1, but we didn't enforce that, // and now there are tests in the wild that call m.Run multiple times. // Sigh. golang.org/issue/23129. m.numRun++ // TestMain may have already called flag.Parse. if !flag.Parsed() { flag.Parse() } if *parallel < 1 { fmt.Fprintln(os.Stderr, "testing: -parallel can only be given a positive integer") flag.Usage() return 2 } if len(*matchList) != 0 { listTests(m.deps.MatchString, m.tests, m.benchmarks, m.examples) return 0 } parseCpuList() m.before() defer m.after() m.startAlarm() haveExamples = len(m.examples) > 0 testRan, testOk := runTests(m.deps.MatchString, m.tests) exampleRan, exampleOk := runExamples(m.deps.MatchString, m.examples) m.stopAlarm() if !testRan && !exampleRan && *matchBenchmarks == "" { fmt.Fprintln(os.Stderr, "testing: warning: no tests to run") } if !testOk || !exampleOk || !runBenchmarks(m.deps.ImportPath(), m.deps.MatchString, m.benchmarks) || race.Errors() > 0 { fmt.Println("FAIL") return 1 } fmt.Println("PASS") return 0 } func (t *T) report() { if t.parent == nil { return } dstr := fmtDuration(t.duration) format := "--- %s: %s (%s)\n" if t.Failed() { t.flushToParent(format, "FAIL", t.name, dstr) } else if t.chatty { if t.Skipped() { t.flushToParent(format, "SKIP", t.name, dstr) } else { t.flushToParent(format, "PASS", t.name, dstr) } } } func listTests(matchString func(pat, str string) (bool, error), tests []InternalTest, benchmarks []InternalBenchmark, examples []InternalExample) { if _, err := matchString(*matchList, "non-empty"); err != nil { fmt.Fprintf(os.Stderr, "testing: invalid regexp in -test.list (%q): %s\n", *matchList, err) os.Exit(1) } for _, test := range tests { if ok, _ := matchString(*matchList, test.Name); ok { fmt.Println(test.Name) } } for _, bench := range benchmarks { if ok, _ := matchString(*matchList, bench.Name); ok { fmt.Println(bench.Name) } } for _, example := range examples { if ok, _ := matchString(*matchList, example.Name); ok { fmt.Println(example.Name) } } } // An internal function but exported because it is cross-package; part of the implementation // of the "go test" command. func RunTests(matchString func(pat, str string) (bool, error), tests []InternalTest) (ok bool) { ran, ok := runTests(matchString, tests) if !ran && !haveExamples { fmt.Fprintln(os.Stderr, "testing: warning: no tests to run") } return ok } func runTests(matchString func(pat, str string) (bool, error), tests []InternalTest) (ran, ok bool) { ok = true for _, procs := range cpuList { runtime.GOMAXPROCS(procs) for i := uint(0); i < *count; i++ { if shouldFailFast() { break } ctx := newTestContext(*parallel, newMatcher(matchString, *match, "-test.run")) t := &T{ common: common{ signal: make(chan bool), barrier: make(chan bool), w: os.Stdout, chatty: *chatty, }, context: ctx, } tRunner(t, func(t *T) { for _, test := range tests { t.Run(test.Name, test.F) } // Run catching the signal rather than the tRunner as a separate // goroutine to avoid adding a goroutine during the sequential // phase as this pollutes the stacktrace output when aborting. go func() { <-t.signal }() }) ok = ok && !t.Failed() ran = ran || t.ran } } return ran, ok } // before runs before all testing. func (m *M) before() { if *memProfileRate > 0 { runtime.MemProfileRate = *memProfileRate } if *cpuProfile != "" { f, err := os.Create(toOutputDir(*cpuProfile)) if err != nil { fmt.Fprintf(os.Stderr, "testing: %s\n", err) return } if err := m.deps.StartCPUProfile(f); err != nil { fmt.Fprintf(os.Stderr, "testing: can't start cpu profile: %s\n", err) f.Close() return } // Could save f so after can call f.Close; not worth the effort. } if *traceFile != "" { f, err := os.Create(toOutputDir(*traceFile)) if err != nil { fmt.Fprintf(os.Stderr, "testing: %s\n", err) return } if err := trace.Start(f); err != nil { fmt.Fprintf(os.Stderr, "testing: can't start tracing: %s\n", err) f.Close() return } // Could save f so after can call f.Close; not worth the effort. } if *blockProfile != "" && *blockProfileRate >= 0 { runtime.SetBlockProfileRate(*blockProfileRate) } if *mutexProfile != "" && *mutexProfileFraction >= 0 { runtime.SetMutexProfileFraction(*mutexProfileFraction) } if *coverProfile != "" && cover.Mode == "" { fmt.Fprintf(os.Stderr, "testing: cannot use -test.coverprofile because test binary was not built with coverage enabled\n") os.Exit(2) } if *testlog != "" { // Note: Not using toOutputDir. // This file is for use by cmd/go, not users. var f *os.File var err error if m.numRun == 1 { f, err = os.Create(*testlog) } else { f, err = os.OpenFile(*testlog, os.O_WRONLY, 0) if err == nil { f.Seek(0, io.SeekEnd) } } if err != nil { fmt.Fprintf(os.Stderr, "testing: %s\n", err) os.Exit(2) } m.deps.StartTestLog(f) testlogFile = f } } // after runs after all testing. func (m *M) after() { m.afterOnce.Do(func() { m.writeProfiles() }) } func (m *M) writeProfiles() { if *testlog != "" { if err := m.deps.StopTestLog(); err != nil { fmt.Fprintf(os.Stderr, "testing: can't write %s: %s\n", *testlog, err) os.Exit(2) } if err := testlogFile.Close(); err != nil { fmt.Fprintf(os.Stderr, "testing: can't write %s: %s\n", *testlog, err) os.Exit(2) } } if *cpuProfile != "" { m.deps.StopCPUProfile() // flushes profile to disk } if *traceFile != "" { trace.Stop() // flushes trace to disk } if *memProfile != "" { f, err := os.Create(toOutputDir(*memProfile)) if err != nil { fmt.Fprintf(os.Stderr, "testing: %s\n", err) os.Exit(2) } runtime.GC() // materialize all statistics if err = m.deps.WriteProfileTo("allocs", f, 0); err != nil { fmt.Fprintf(os.Stderr, "testing: can't write %s: %s\n", *memProfile, err) os.Exit(2) } f.Close() } if *blockProfile != "" && *blockProfileRate >= 0 { f, err := os.Create(toOutputDir(*blockProfile)) if err != nil { fmt.Fprintf(os.Stderr, "testing: %s\n", err) os.Exit(2) } if err = m.deps.WriteProfileTo("block", f, 0); err != nil { fmt.Fprintf(os.Stderr, "testing: can't write %s: %s\n", *blockProfile, err) os.Exit(2) } f.Close() } if *mutexProfile != "" && *mutexProfileFraction >= 0 { f, err := os.Create(toOutputDir(*mutexProfile)) if err != nil { fmt.Fprintf(os.Stderr, "testing: %s\n", err) os.Exit(2) } if err = m.deps.WriteProfileTo("mutex", f, 0); err != nil { fmt.Fprintf(os.Stderr, "testing: can't write %s: %s\n", *blockProfile, err) os.Exit(2) } f.Close() } if cover.Mode != "" { coverReport() } } // toOutputDir returns the file name relocated, if required, to outputDir. // Simple implementation to avoid pulling in path/filepath. func toOutputDir(path string) string { if *outputDir == "" || path == "" { return path } if runtime.GOOS == "windows" { // On Windows, it's clumsy, but we can be almost always correct // by just looking for a drive letter and a colon. // Absolute paths always have a drive letter (ignoring UNC). // Problem: if path == "C:A" and outputdir == "C:\Go" it's unclear // what to do, but even then path/filepath doesn't help. // TODO: Worth doing better? Probably not, because we're here only // under the management of go test. if len(path) >= 2 { letter, colon := path[0], path[1] if ('a' <= letter && letter <= 'z' || 'A' <= letter && letter <= 'Z') && colon == ':' { // If path starts with a drive letter we're stuck with it regardless. return path } } } if os.IsPathSeparator(path[0]) { return path } return fmt.Sprintf("%s%c%s", *outputDir, os.PathSeparator, path) } // startAlarm starts an alarm if requested. func (m *M) startAlarm() { if *timeout > 0 { m.timer = time.AfterFunc(*timeout, func() { m.after() debug.SetTraceback("all") panic(fmt.Sprintf("test timed out after %v", *timeout)) }) } } // stopAlarm turns off the alarm. func (m *M) stopAlarm() { if *timeout > 0 { m.timer.Stop() } } func parseCpuList() { for _, val := range strings.Split(*cpuListStr, ",") { val = strings.TrimSpace(val) if val == "" { continue } cpu, err := strconv.Atoi(val) if err != nil || cpu <= 0 { fmt.Fprintf(os.Stderr, "testing: invalid value %q for -test.cpu\n", val) os.Exit(1) } cpuList = append(cpuList, cpu) } if cpuList == nil { cpuList = append(cpuList, runtime.GOMAXPROCS(-1)) } } func shouldFailFast() bool { return *failFast && atomic.LoadUint32(&numFailed) > 0 }