Go语言context test源码分析详情

func ExampleWithCancel() {
  gen := func(ctx context.Context) <-chan int {
    dst := make(chan int)
    n := 1
    go func() {
      for {
        select {
        case <-ctx.Done():
          return // returning not to leak the goroutine
        case dst <- n:
          n++
        }
      }
    }()
    return dst
  }

  ctx, cancel := context.WithCancel(context.Background())
  defer cancel() // cancel when we are finished consuming integers

  for n := range gen(ctx) {
    fmt.Println(n)
    if n == 5 {
      break
    }
  }
  // Output:
  // 1
  // 2
  // 3
  // 4
  // 5
}

const shortDuration = 1 * time.Millisecond
func ExampleWithDeadline() {
  d := time.Now().Add(shortDuration)
  ctx, cancel := context.WithDeadline(context.Background(), d)

  // Even though ctx will be expired, it is good practice to call its
  // cancellation function in any case. Failure to do so may keep the
  // context and its parent alive longer than necessary.
  defer cancel()

  select {
  case <-time.After(1 * time.Second):
    fmt.Println("overslept")
  case <-ctx.Done():
    fmt.Println(ctx.Err())
  }

  // Output:
  // context deadline exceeded
}

func ExampleWithTimeout() {
  ctx, cancel := context.WithTimeout(context.Background(), shortDuration)
  defer cancel()

  select {
  case <-time.After(1 * time.Second):
    fmt.Println("overslept")
  case <-ctx.Done():
    fmt.Println(ctx.Err()) // prints "context deadline exceeded"
  }

  // Output:
  // context deadline exceeded
}

func ExampleWithValue() {
  type favContextKey string

  f := func(ctx context.Context, k favContextKey) {
    if v := ctx.Value(k); v != nil {
      fmt.Println("found value:", v)
      return
    }
    fmt.Println("key not found:", k)
  }

  k := favContextKey("language")
  ctx := context.WithValue(context.Background(), k, "Go")

  f(ctx, k)
  f(ctx, favContextKey("color"))

  // Output:
  // found value: Go
  // key not found: color
}

type testingT interface {}

type otherContext struct {}
func quiescent(t testingT) time.Duration {}
func XTestBackground(t testingT) {}
func XTestTODO(t testingT) {}
func XTestWithCancel(t testingT) {}
func contains(m map[canceler]struct{}, key canceler) bool {}
func XTestParentFinishesChild(t testingT) {}
func XTestChildFinishesFirst(t testingT) {}
func testDeadline(c Context, name string, t testingT) {}
func XTestDeadline(t testingT) {}
func XTestTimeout(t testingT) {}
func XTestCanceledTimeout(t testingT) {}
func XTestValues(t testingT) {}
func XTestAllocs(t testingT, testingShort func() bool, testingAllocsPerRun func(int, func()) float64) {}
func XTestSimultaneousCancels(t testingT) {}
func XTestInterlockedCancels(t testingT) {}
func XTestLayersCancel(t testingT) {}
func XTestLayersTimeout(t testingT) {}
func XTestCancelRemoves(t testingT) {}
func XTestWithCancelCanceledParent(t testingT) {}
func XTestWithValueChecksKey(t testingT) {}
func XTestInvalidDerivedFail(t testingT) {}
func recoveredValue(fn func()) (v interface{}) {}
func XTestDeadlineExceededSupportsTimeout(t testingT) {}
type myCtx struct {}
type myDoneCtx struct {}
func (d *myDoneCtx) Done() <-chan struct{} {}
func XTestCustomContextGoroutines(t testingT) {}

func TestBackground(t *testing.T)                      { XTestBackground(t) }
func TestTODO(t *testing.T)                            { XTestTODO(t) }
func TestWithCancel(t *testing.T)                      { XTestWithCancel(t) }
func TestParentFinishesChild(t *testing.T)             { XTestParentFinishesChild(t) }
func TestChildFinishesFirst(t *testing.T)              { XTestChildFinishesFirst(t) }
func TestDeadline(t *testing.T)                        { XTestDeadline(t) }
func TestTimeout(t *testing.T)                         { XTestTimeout(t) }
func TestCanceledTimeout(t *testing.T)                 { XTestCanceledTimeout(t) }
func TestValues(t *testing.T)                          { XTestValues(t) }
func TestAllocs(t *testing.T)                          { XTestAllocs(t, testing.Short, testing.AllocsPerRun) }
func TestSimultaneousCancels(t *testing.T)             { XTestSimultaneousCancels(t) }
func TestInterlockedCancels(t *testing.T)              { XTestInterlockedCancels(t) }
func TestLayersCancel(t *testing.T)                    { XTestLayersCancel(t) }
func TestLayersTimeout(t *testing.T)                   { XTestLayersTimeout(t) }
func TestCancelRemoves(t *testing.T)                   { XTestCancelRemoves(t) }
func TestWithCancelCanceledParent(t *testing.T)        { XTestWithCancelCanceledParent(t) }
func TestWithValueChecksKey(t *testing.T)              { XTestWithValueChecksKey(t) }
func TestInvalidDerivedFail(t *testing.T)              { XTestInvalidDerivedFail(t) }
func TestDeadlineExceededSupportsTimeout(t *testing.T) { XTestDeadlineExceededSupportsTimeout(t) }
func TestCustomContextGoroutines(t *testing.T)         { XTestCustomContextGoroutines(t) }

type T struct {
  common
  isParallel bool
  context    *testContext
}
func (t *T) Deadline() (deadline time.Time, ok bool) {
  deadline = t.context.deadline
  return deadline, !deadline.IsZero()
}

Error(args ...interface{})
Errorf(format string, args ...interface{})
Fail()
FailNow()
Failed() bool
Fatal(args ...interface{})
Fatalf(format string, args ...interface{})
Helper()
Log(args ...interface{})
Logf(format string, args ...interface{})
Name() string
Skip(args ...interface{})
SkipNow()
Skipf(format string, args ...interface{})
Skipped() bool