diff options
Diffstat (limited to 'src/context/context_test.go')
-rw-r--r-- | src/context/context_test.go | 956 |
1 files changed, 956 insertions, 0 deletions
diff --git a/src/context/context_test.go b/src/context/context_test.go new file mode 100644 index 0000000..1c770cd --- /dev/null +++ b/src/context/context_test.go @@ -0,0 +1,956 @@ +// Copyright 2014 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 context + +import ( + "errors" + "fmt" + "math/rand" + "runtime" + "strings" + "sync" + "time" +) + +type testingT interface { + Deadline() (time.Time, bool) + Error(args ...any) + Errorf(format string, args ...any) + Fail() + FailNow() + Failed() bool + Fatal(args ...any) + Fatalf(format string, args ...any) + Helper() + Log(args ...any) + Logf(format string, args ...any) + Name() string + Parallel() + Skip(args ...any) + SkipNow() + Skipf(format string, args ...any) + Skipped() bool +} + +// otherContext is a Context that's not one of the types defined in context.go. +// This lets us test code paths that differ based on the underlying type of the +// Context. +type otherContext struct { + Context +} + +const ( + shortDuration = 1 * time.Millisecond // a reasonable duration to block in a test + veryLongDuration = 1000 * time.Hour // an arbitrary upper bound on the test's running time +) + +// quiescent returns an arbitrary duration by which the program should have +// completed any remaining work and reached a steady (idle) state. +func quiescent(t testingT) time.Duration { + deadline, ok := t.Deadline() + if !ok { + return 5 * time.Second + } + + const arbitraryCleanupMargin = 1 * time.Second + return time.Until(deadline) - arbitraryCleanupMargin +} + +func XTestBackground(t testingT) { + c := Background() + if c == nil { + t.Fatalf("Background returned nil") + } + select { + case x := <-c.Done(): + t.Errorf("<-c.Done() == %v want nothing (it should block)", x) + default: + } + if got, want := fmt.Sprint(c), "context.Background"; got != want { + t.Errorf("Background().String() = %q want %q", got, want) + } +} + +func XTestTODO(t testingT) { + c := TODO() + if c == nil { + t.Fatalf("TODO returned nil") + } + select { + case x := <-c.Done(): + t.Errorf("<-c.Done() == %v want nothing (it should block)", x) + default: + } + if got, want := fmt.Sprint(c), "context.TODO"; got != want { + t.Errorf("TODO().String() = %q want %q", got, want) + } +} + +func XTestWithCancel(t testingT) { + c1, cancel := WithCancel(Background()) + + if got, want := fmt.Sprint(c1), "context.Background.WithCancel"; got != want { + t.Errorf("c1.String() = %q want %q", got, want) + } + + o := otherContext{c1} + c2, _ := WithCancel(o) + contexts := []Context{c1, o, c2} + + for i, c := range contexts { + if d := c.Done(); d == nil { + t.Errorf("c[%d].Done() == %v want non-nil", i, d) + } + if e := c.Err(); e != nil { + t.Errorf("c[%d].Err() == %v want nil", i, e) + } + + select { + case x := <-c.Done(): + t.Errorf("<-c.Done() == %v want nothing (it should block)", x) + default: + } + } + + cancel() // Should propagate synchronously. + for i, c := range contexts { + select { + case <-c.Done(): + default: + t.Errorf("<-c[%d].Done() blocked, but shouldn't have", i) + } + if e := c.Err(); e != Canceled { + t.Errorf("c[%d].Err() == %v want %v", i, e, Canceled) + } + } +} + +func contains(m map[canceler]struct{}, key canceler) bool { + _, ret := m[key] + return ret +} + +func XTestParentFinishesChild(t testingT) { + // Context tree: + // parent -> cancelChild + // parent -> valueChild -> timerChild + parent, cancel := WithCancel(Background()) + cancelChild, stop := WithCancel(parent) + defer stop() + valueChild := WithValue(parent, "key", "value") + timerChild, stop := WithTimeout(valueChild, veryLongDuration) + defer stop() + + select { + case x := <-parent.Done(): + t.Errorf("<-parent.Done() == %v want nothing (it should block)", x) + case x := <-cancelChild.Done(): + t.Errorf("<-cancelChild.Done() == %v want nothing (it should block)", x) + case x := <-timerChild.Done(): + t.Errorf("<-timerChild.Done() == %v want nothing (it should block)", x) + case x := <-valueChild.Done(): + t.Errorf("<-valueChild.Done() == %v want nothing (it should block)", x) + default: + } + + // The parent's children should contain the two cancelable children. + pc := parent.(*cancelCtx) + cc := cancelChild.(*cancelCtx) + tc := timerChild.(*timerCtx) + pc.mu.Lock() + if len(pc.children) != 2 || !contains(pc.children, cc) || !contains(pc.children, tc) { + t.Errorf("bad linkage: pc.children = %v, want %v and %v", + pc.children, cc, tc) + } + pc.mu.Unlock() + + if p, ok := parentCancelCtx(cc.Context); !ok || p != pc { + t.Errorf("bad linkage: parentCancelCtx(cancelChild.Context) = %v, %v want %v, true", p, ok, pc) + } + if p, ok := parentCancelCtx(tc.Context); !ok || p != pc { + t.Errorf("bad linkage: parentCancelCtx(timerChild.Context) = %v, %v want %v, true", p, ok, pc) + } + + cancel() + + pc.mu.Lock() + if len(pc.children) != 0 { + t.Errorf("pc.cancel didn't clear pc.children = %v", pc.children) + } + pc.mu.Unlock() + + // parent and children should all be finished. + check := func(ctx Context, name string) { + select { + case <-ctx.Done(): + default: + t.Errorf("<-%s.Done() blocked, but shouldn't have", name) + } + if e := ctx.Err(); e != Canceled { + t.Errorf("%s.Err() == %v want %v", name, e, Canceled) + } + } + check(parent, "parent") + check(cancelChild, "cancelChild") + check(valueChild, "valueChild") + check(timerChild, "timerChild") + + // WithCancel should return a canceled context on a canceled parent. + precanceledChild := WithValue(parent, "key", "value") + select { + case <-precanceledChild.Done(): + default: + t.Errorf("<-precanceledChild.Done() blocked, but shouldn't have") + } + if e := precanceledChild.Err(); e != Canceled { + t.Errorf("precanceledChild.Err() == %v want %v", e, Canceled) + } +} + +func XTestChildFinishesFirst(t testingT) { + cancelable, stop := WithCancel(Background()) + defer stop() + for _, parent := range []Context{Background(), cancelable} { + child, cancel := WithCancel(parent) + + select { + case x := <-parent.Done(): + t.Errorf("<-parent.Done() == %v want nothing (it should block)", x) + case x := <-child.Done(): + t.Errorf("<-child.Done() == %v want nothing (it should block)", x) + default: + } + + cc := child.(*cancelCtx) + pc, pcok := parent.(*cancelCtx) // pcok == false when parent == Background() + if p, ok := parentCancelCtx(cc.Context); ok != pcok || (ok && pc != p) { + t.Errorf("bad linkage: parentCancelCtx(cc.Context) = %v, %v want %v, %v", p, ok, pc, pcok) + } + + if pcok { + pc.mu.Lock() + if len(pc.children) != 1 || !contains(pc.children, cc) { + t.Errorf("bad linkage: pc.children = %v, cc = %v", pc.children, cc) + } + pc.mu.Unlock() + } + + cancel() + + if pcok { + pc.mu.Lock() + if len(pc.children) != 0 { + t.Errorf("child's cancel didn't remove self from pc.children = %v", pc.children) + } + pc.mu.Unlock() + } + + // child should be finished. + select { + case <-child.Done(): + default: + t.Errorf("<-child.Done() blocked, but shouldn't have") + } + if e := child.Err(); e != Canceled { + t.Errorf("child.Err() == %v want %v", e, Canceled) + } + + // parent should not be finished. + select { + case x := <-parent.Done(): + t.Errorf("<-parent.Done() == %v want nothing (it should block)", x) + default: + } + if e := parent.Err(); e != nil { + t.Errorf("parent.Err() == %v want nil", e) + } + } +} + +func testDeadline(c Context, name string, t testingT) { + t.Helper() + d := quiescent(t) + timer := time.NewTimer(d) + defer timer.Stop() + select { + case <-timer.C: + t.Fatalf("%s: context not timed out after %v", name, d) + case <-c.Done(): + } + if e := c.Err(); e != DeadlineExceeded { + t.Errorf("%s: c.Err() == %v; want %v", name, e, DeadlineExceeded) + } +} + +func XTestDeadline(t testingT) { + t.Parallel() + + c, _ := WithDeadline(Background(), time.Now().Add(shortDuration)) + if got, prefix := fmt.Sprint(c), "context.Background.WithDeadline("; !strings.HasPrefix(got, prefix) { + t.Errorf("c.String() = %q want prefix %q", got, prefix) + } + testDeadline(c, "WithDeadline", t) + + c, _ = WithDeadline(Background(), time.Now().Add(shortDuration)) + o := otherContext{c} + testDeadline(o, "WithDeadline+otherContext", t) + + c, _ = WithDeadline(Background(), time.Now().Add(shortDuration)) + o = otherContext{c} + c, _ = WithDeadline(o, time.Now().Add(veryLongDuration)) + testDeadline(c, "WithDeadline+otherContext+WithDeadline", t) + + c, _ = WithDeadline(Background(), time.Now().Add(-shortDuration)) + testDeadline(c, "WithDeadline+inthepast", t) + + c, _ = WithDeadline(Background(), time.Now()) + testDeadline(c, "WithDeadline+now", t) +} + +func XTestTimeout(t testingT) { + t.Parallel() + + c, _ := WithTimeout(Background(), shortDuration) + if got, prefix := fmt.Sprint(c), "context.Background.WithDeadline("; !strings.HasPrefix(got, prefix) { + t.Errorf("c.String() = %q want prefix %q", got, prefix) + } + testDeadline(c, "WithTimeout", t) + + c, _ = WithTimeout(Background(), shortDuration) + o := otherContext{c} + testDeadline(o, "WithTimeout+otherContext", t) + + c, _ = WithTimeout(Background(), shortDuration) + o = otherContext{c} + c, _ = WithTimeout(o, veryLongDuration) + testDeadline(c, "WithTimeout+otherContext+WithTimeout", t) +} + +func XTestCanceledTimeout(t testingT) { + c, _ := WithTimeout(Background(), time.Second) + o := otherContext{c} + c, cancel := WithTimeout(o, veryLongDuration) + cancel() // Should propagate synchronously. + select { + case <-c.Done(): + default: + t.Errorf("<-c.Done() blocked, but shouldn't have") + } + if e := c.Err(); e != Canceled { + t.Errorf("c.Err() == %v want %v", e, Canceled) + } +} + +type key1 int +type key2 int + +var k1 = key1(1) +var k2 = key2(1) // same int as k1, different type +var k3 = key2(3) // same type as k2, different int + +func XTestValues(t testingT) { + check := func(c Context, nm, v1, v2, v3 string) { + if v, ok := c.Value(k1).(string); ok == (len(v1) == 0) || v != v1 { + t.Errorf(`%s.Value(k1).(string) = %q, %t want %q, %t`, nm, v, ok, v1, len(v1) != 0) + } + if v, ok := c.Value(k2).(string); ok == (len(v2) == 0) || v != v2 { + t.Errorf(`%s.Value(k2).(string) = %q, %t want %q, %t`, nm, v, ok, v2, len(v2) != 0) + } + if v, ok := c.Value(k3).(string); ok == (len(v3) == 0) || v != v3 { + t.Errorf(`%s.Value(k3).(string) = %q, %t want %q, %t`, nm, v, ok, v3, len(v3) != 0) + } + } + + c0 := Background() + check(c0, "c0", "", "", "") + + c1 := WithValue(Background(), k1, "c1k1") + check(c1, "c1", "c1k1", "", "") + + if got, want := fmt.Sprint(c1), `context.Background.WithValue(type context.key1, val c1k1)`; got != want { + t.Errorf("c.String() = %q want %q", got, want) + } + + c2 := WithValue(c1, k2, "c2k2") + check(c2, "c2", "c1k1", "c2k2", "") + + c3 := WithValue(c2, k3, "c3k3") + check(c3, "c2", "c1k1", "c2k2", "c3k3") + + c4 := WithValue(c3, k1, nil) + check(c4, "c4", "", "c2k2", "c3k3") + + o0 := otherContext{Background()} + check(o0, "o0", "", "", "") + + o1 := otherContext{WithValue(Background(), k1, "c1k1")} + check(o1, "o1", "c1k1", "", "") + + o2 := WithValue(o1, k2, "o2k2") + check(o2, "o2", "c1k1", "o2k2", "") + + o3 := otherContext{c4} + check(o3, "o3", "", "c2k2", "c3k3") + + o4 := WithValue(o3, k3, nil) + check(o4, "o4", "", "c2k2", "") +} + +func XTestAllocs(t testingT, testingShort func() bool, testingAllocsPerRun func(int, func()) float64) { + bg := Background() + for _, test := range []struct { + desc string + f func() + limit float64 + gccgoLimit float64 + }{ + { + desc: "Background()", + f: func() { Background() }, + limit: 0, + gccgoLimit: 0, + }, + { + desc: fmt.Sprintf("WithValue(bg, %v, nil)", k1), + f: func() { + c := WithValue(bg, k1, nil) + c.Value(k1) + }, + limit: 3, + gccgoLimit: 3, + }, + { + desc: "WithTimeout(bg, 1*time.Nanosecond)", + f: func() { + c, _ := WithTimeout(bg, 1*time.Nanosecond) + <-c.Done() + }, + limit: 12, + gccgoLimit: 15, + }, + { + desc: "WithCancel(bg)", + f: func() { + c, cancel := WithCancel(bg) + cancel() + <-c.Done() + }, + limit: 5, + gccgoLimit: 8, + }, + { + desc: "WithTimeout(bg, 5*time.Millisecond)", + f: func() { + c, cancel := WithTimeout(bg, 5*time.Millisecond) + cancel() + <-c.Done() + }, + limit: 8, + gccgoLimit: 25, + }, + } { + limit := test.limit + if runtime.Compiler == "gccgo" { + // gccgo does not yet do escape analysis. + // TODO(iant): Remove this when gccgo does do escape analysis. + limit = test.gccgoLimit + } + numRuns := 100 + if testingShort() { + numRuns = 10 + } + if n := testingAllocsPerRun(numRuns, test.f); n > limit { + t.Errorf("%s allocs = %f want %d", test.desc, n, int(limit)) + } + } +} + +func XTestSimultaneousCancels(t testingT) { + root, cancel := WithCancel(Background()) + m := map[Context]CancelFunc{root: cancel} + q := []Context{root} + // Create a tree of contexts. + for len(q) != 0 && len(m) < 100 { + parent := q[0] + q = q[1:] + for i := 0; i < 4; i++ { + ctx, cancel := WithCancel(parent) + m[ctx] = cancel + q = append(q, ctx) + } + } + // Start all the cancels in a random order. + var wg sync.WaitGroup + wg.Add(len(m)) + for _, cancel := range m { + go func(cancel CancelFunc) { + cancel() + wg.Done() + }(cancel) + } + + d := quiescent(t) + stuck := make(chan struct{}) + timer := time.AfterFunc(d, func() { close(stuck) }) + defer timer.Stop() + + // Wait on all the contexts in a random order. + for ctx := range m { + select { + case <-ctx.Done(): + case <-stuck: + buf := make([]byte, 10<<10) + n := runtime.Stack(buf, true) + t.Fatalf("timed out after %v waiting for <-ctx.Done(); stacks:\n%s", d, buf[:n]) + } + } + // Wait for all the cancel functions to return. + done := make(chan struct{}) + go func() { + wg.Wait() + close(done) + }() + select { + case <-done: + case <-stuck: + buf := make([]byte, 10<<10) + n := runtime.Stack(buf, true) + t.Fatalf("timed out after %v waiting for cancel functions; stacks:\n%s", d, buf[:n]) + } +} + +func XTestInterlockedCancels(t testingT) { + parent, cancelParent := WithCancel(Background()) + child, cancelChild := WithCancel(parent) + go func() { + <-parent.Done() + cancelChild() + }() + cancelParent() + d := quiescent(t) + timer := time.NewTimer(d) + defer timer.Stop() + select { + case <-child.Done(): + case <-timer.C: + buf := make([]byte, 10<<10) + n := runtime.Stack(buf, true) + t.Fatalf("timed out after %v waiting for child.Done(); stacks:\n%s", d, buf[:n]) + } +} + +func XTestLayersCancel(t testingT) { + testLayers(t, time.Now().UnixNano(), false) +} + +func XTestLayersTimeout(t testingT) { + testLayers(t, time.Now().UnixNano(), true) +} + +func testLayers(t testingT, seed int64, testTimeout bool) { + t.Parallel() + + r := rand.New(rand.NewSource(seed)) + errorf := func(format string, a ...any) { + t.Errorf(fmt.Sprintf("seed=%d: %s", seed, format), a...) + } + const ( + minLayers = 30 + ) + type value int + var ( + vals []*value + cancels []CancelFunc + numTimers int + ctx = Background() + ) + for i := 0; i < minLayers || numTimers == 0 || len(cancels) == 0 || len(vals) == 0; i++ { + switch r.Intn(3) { + case 0: + v := new(value) + ctx = WithValue(ctx, v, v) + vals = append(vals, v) + case 1: + var cancel CancelFunc + ctx, cancel = WithCancel(ctx) + cancels = append(cancels, cancel) + case 2: + var cancel CancelFunc + d := veryLongDuration + if testTimeout { + d = shortDuration + } + ctx, cancel = WithTimeout(ctx, d) + cancels = append(cancels, cancel) + numTimers++ + } + } + checkValues := func(when string) { + for _, key := range vals { + if val := ctx.Value(key).(*value); key != val { + errorf("%s: ctx.Value(%p) = %p want %p", when, key, val, key) + } + } + } + if !testTimeout { + select { + case <-ctx.Done(): + errorf("ctx should not be canceled yet") + default: + } + } + if s, prefix := fmt.Sprint(ctx), "context.Background."; !strings.HasPrefix(s, prefix) { + t.Errorf("ctx.String() = %q want prefix %q", s, prefix) + } + t.Log(ctx) + checkValues("before cancel") + if testTimeout { + d := quiescent(t) + timer := time.NewTimer(d) + defer timer.Stop() + select { + case <-ctx.Done(): + case <-timer.C: + errorf("ctx should have timed out after %v", d) + } + checkValues("after timeout") + } else { + cancel := cancels[r.Intn(len(cancels))] + cancel() + select { + case <-ctx.Done(): + default: + errorf("ctx should be canceled") + } + checkValues("after cancel") + } +} + +func XTestCancelRemoves(t testingT) { + checkChildren := func(when string, ctx Context, want int) { + if got := len(ctx.(*cancelCtx).children); got != want { + t.Errorf("%s: context has %d children, want %d", when, got, want) + } + } + + ctx, _ := WithCancel(Background()) + checkChildren("after creation", ctx, 0) + _, cancel := WithCancel(ctx) + checkChildren("with WithCancel child ", ctx, 1) + cancel() + checkChildren("after canceling WithCancel child", ctx, 0) + + ctx, _ = WithCancel(Background()) + checkChildren("after creation", ctx, 0) + _, cancel = WithTimeout(ctx, 60*time.Minute) + checkChildren("with WithTimeout child ", ctx, 1) + cancel() + checkChildren("after canceling WithTimeout child", ctx, 0) +} + +func XTestWithCancelCanceledParent(t testingT) { + parent, pcancel := WithCancelCause(Background()) + cause := fmt.Errorf("Because!") + pcancel(cause) + + c, _ := WithCancel(parent) + select { + case <-c.Done(): + default: + t.Errorf("child not done immediately upon construction") + } + if got, want := c.Err(), Canceled; got != want { + t.Errorf("child not canceled; got = %v, want = %v", got, want) + } + if got, want := Cause(c), cause; got != want { + t.Errorf("child has wrong cause; got = %v, want = %v", got, want) + } +} + +func XTestWithValueChecksKey(t testingT) { + panicVal := recoveredValue(func() { _ = WithValue(Background(), []byte("foo"), "bar") }) + if panicVal == nil { + t.Error("expected panic") + } + panicVal = recoveredValue(func() { _ = WithValue(Background(), nil, "bar") }) + if got, want := fmt.Sprint(panicVal), "nil key"; got != want { + t.Errorf("panic = %q; want %q", got, want) + } +} + +func XTestInvalidDerivedFail(t testingT) { + panicVal := recoveredValue(func() { _, _ = WithCancel(nil) }) + if panicVal == nil { + t.Error("expected panic") + } + panicVal = recoveredValue(func() { _, _ = WithDeadline(nil, time.Now().Add(shortDuration)) }) + if panicVal == nil { + t.Error("expected panic") + } + panicVal = recoveredValue(func() { _ = WithValue(nil, "foo", "bar") }) + if panicVal == nil { + t.Error("expected panic") + } +} + +func recoveredValue(fn func()) (v any) { + defer func() { v = recover() }() + fn() + return +} + +func XTestDeadlineExceededSupportsTimeout(t testingT) { + i, ok := DeadlineExceeded.(interface { + Timeout() bool + }) + if !ok { + t.Fatal("DeadlineExceeded does not support Timeout interface") + } + if !i.Timeout() { + t.Fatal("wrong value for timeout") + } +} + +type myCtx struct { + Context +} + +type myDoneCtx struct { + Context +} + +func (d *myDoneCtx) Done() <-chan struct{} { + c := make(chan struct{}) + return c +} + +func XTestCustomContextGoroutines(t testingT) { + g := goroutines.Load() + checkNoGoroutine := func() { + t.Helper() + now := goroutines.Load() + if now != g { + t.Fatalf("%d goroutines created", now-g) + } + } + checkCreatedGoroutine := func() { + t.Helper() + now := goroutines.Load() + if now != g+1 { + t.Fatalf("%d goroutines created, want 1", now-g) + } + g = now + } + + _, cancel0 := WithCancel(&myDoneCtx{Background()}) + cancel0() + checkCreatedGoroutine() + + _, cancel0 = WithTimeout(&myDoneCtx{Background()}, veryLongDuration) + cancel0() + checkCreatedGoroutine() + + checkNoGoroutine() + defer checkNoGoroutine() + + ctx1, cancel1 := WithCancel(Background()) + defer cancel1() + checkNoGoroutine() + + ctx2 := &myCtx{ctx1} + ctx3, cancel3 := WithCancel(ctx2) + defer cancel3() + checkNoGoroutine() + + _, cancel3b := WithCancel(&myDoneCtx{ctx2}) + defer cancel3b() + checkCreatedGoroutine() // ctx1 is not providing Done, must not be used + + ctx4, cancel4 := WithTimeout(ctx3, veryLongDuration) + defer cancel4() + checkNoGoroutine() + + ctx5, cancel5 := WithCancel(ctx4) + defer cancel5() + checkNoGoroutine() + + cancel5() + checkNoGoroutine() + + _, cancel6 := WithTimeout(ctx5, veryLongDuration) + defer cancel6() + checkNoGoroutine() + + // Check applied to canceled context. + cancel6() + cancel1() + _, cancel7 := WithCancel(ctx5) + defer cancel7() + checkNoGoroutine() +} + +func XTestCause(t testingT) { + var ( + parentCause = fmt.Errorf("parentCause") + childCause = fmt.Errorf("childCause") + ) + for _, test := range []struct { + name string + ctx Context + err error + cause error + }{ + { + name: "Background", + ctx: Background(), + err: nil, + cause: nil, + }, + { + name: "TODO", + ctx: TODO(), + err: nil, + cause: nil, + }, + { + name: "WithCancel", + ctx: func() Context { + ctx, cancel := WithCancel(Background()) + cancel() + return ctx + }(), + err: Canceled, + cause: Canceled, + }, + { + name: "WithCancelCause", + ctx: func() Context { + ctx, cancel := WithCancelCause(Background()) + cancel(parentCause) + return ctx + }(), + err: Canceled, + cause: parentCause, + }, + { + name: "WithCancelCause nil", + ctx: func() Context { + ctx, cancel := WithCancelCause(Background()) + cancel(nil) + return ctx + }(), + err: Canceled, + cause: Canceled, + }, + { + name: "WithCancelCause: parent cause before child", + ctx: func() Context { + ctx, cancelParent := WithCancelCause(Background()) + ctx, cancelChild := WithCancelCause(ctx) + cancelParent(parentCause) + cancelChild(childCause) + return ctx + }(), + err: Canceled, + cause: parentCause, + }, + { + name: "WithCancelCause: parent cause after child", + ctx: func() Context { + ctx, cancelParent := WithCancelCause(Background()) + ctx, cancelChild := WithCancelCause(ctx) + cancelChild(childCause) + cancelParent(parentCause) + return ctx + }(), + err: Canceled, + cause: childCause, + }, + { + name: "WithCancelCause: parent cause before nil", + ctx: func() Context { + ctx, cancelParent := WithCancelCause(Background()) + ctx, cancelChild := WithCancel(ctx) + cancelParent(parentCause) + cancelChild() + return ctx + }(), + err: Canceled, + cause: parentCause, + }, + { + name: "WithCancelCause: parent cause after nil", + ctx: func() Context { + ctx, cancelParent := WithCancelCause(Background()) + ctx, cancelChild := WithCancel(ctx) + cancelChild() + cancelParent(parentCause) + return ctx + }(), + err: Canceled, + cause: Canceled, + }, + { + name: "WithCancelCause: child cause after nil", + ctx: func() Context { + ctx, cancelParent := WithCancel(Background()) + ctx, cancelChild := WithCancelCause(ctx) + cancelParent() + cancelChild(childCause) + return ctx + }(), + err: Canceled, + cause: Canceled, + }, + { + name: "WithCancelCause: child cause before nil", + ctx: func() Context { + ctx, cancelParent := WithCancel(Background()) + ctx, cancelChild := WithCancelCause(ctx) + cancelChild(childCause) + cancelParent() + return ctx + }(), + err: Canceled, + cause: childCause, + }, + { + name: "WithTimeout", + ctx: func() Context { + ctx, cancel := WithTimeout(Background(), 0) + cancel() + return ctx + }(), + err: DeadlineExceeded, + cause: DeadlineExceeded, + }, + } { + if got, want := test.ctx.Err(), test.err; want != got { + t.Errorf("%s: ctx.Err() = %v want %v", test.name, got, want) + } + if got, want := Cause(test.ctx), test.cause; want != got { + t.Errorf("%s: Cause(ctx) = %v want %v", test.name, got, want) + } + } +} + +func XTestCauseRace(t testingT) { + cause := errors.New("TestCauseRace") + ctx, cancel := WithCancelCause(Background()) + go func() { + cancel(cause) + }() + for { + // Poll Cause, rather than waiting for Done, to test that + // access to the underlying cause is synchronized properly. + if err := Cause(ctx); err != nil { + if err != cause { + t.Errorf("Cause returned %v, want %v", err, cause) + } + break + } + runtime.Gosched() + } +} |