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// 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
}