✨ [pkg/test] Add context to ConcurrentT.

ConcurrentT can now be constructed with an optional context which will
cause all stages and waiting operations to fail on expiry.

Signed-off-by: Steffen Rattay <steffen@perun.network>

Author: RmbRT

pkg/test/concurrent.go

@@ -15,6 +15,7 @@
 package test
 
 import (
+	"context"
 	"runtime"
 	"strconv"
 	"strings"
@@ -130,17 +131,26 @@ type ConcurrentT struct {
 	t            require.TestingT
 	failed       bool
 	failedCh     chan struct{}
+	ctx          context.Context
 
 	mutex  sync.Mutex
 	stages map[string]*stage
 }
 
 // NewConcurrent creates a new concurrent testing object.
 func NewConcurrent(t require.TestingT) *ConcurrentT {
+	return NewConcurrentCtx(t, context.Background())
+}
+
+// NewConcurrentCtx creates a new concurrent testing object controlled by a
+// context. If that context expires, any ongoing stages and wait calls will
+// fail.
+func NewConcurrentCtx(t require.TestingT, ctx context.Context) *ConcurrentT {
 	return &ConcurrentT{
 		t:        t,
 		stages:   make(map[string]*stage),
 		failedCh: make(chan struct{}),
+		ctx:      ctx,
 	}
 }
 
@@ -167,8 +177,10 @@ func (t *ConcurrentT) getStage(name string) *stage {
 	return s
 }
 
-// Wait waits until the stages and barriers with the requested names terminate.
-// If any stage or barrier fails, terminates the current goroutine or test.
+// Wait waits until the stages and barriers with the requested names
+// terminate or the test's context expires. If the context expires, fails the
+// test. If any stage or barrier fails, terminates the current goroutine or
+// test.
 func (t *ConcurrentT) Wait(names ...string) {
 	if len(names) == 0 {
 		panic("Wait(): called with 0 names")
@@ -177,6 +189,8 @@ func (t *ConcurrentT) Wait(names ...string) {
 	for _, name := range names {
 		stage := t.getStage(name)
 		select {
+		case <-t.ctx.Done():
+			t.FailNow()
 		case <-stage.wg.WaitCh():
 			if stage.failed.IsSet() {
 				t.FailNow()
@@ -209,28 +223,36 @@ func (t *ConcurrentT) FailNow() {
 // fn must not spawn any goroutines or pass along the T object to goroutines
 // that call T.Fatal. To achieve this, make other goroutines call
 // ConcurrentT.StageN() instead.
+// If the test's context expires before the call returns, fails the test.
 func (t *ConcurrentT) StageN(name string, goroutines int, fn func(ConcT)) {
 	stage := t.spawnStage(name, goroutines)
 
 	stageT := ConcT{TestingT: stage, ct: t}
-	abort := CheckAbort(func() {
+	abort, ok := CheckAbortCtx(t.ctx, func() {
 		fn(stageT)
 	})
 
-	if abort != nil {
-		// Fail the stage, if it had not been marked as such, yet.
-		if stage.failed.TrySet() {
-			defer stage.wg.Done()
-		}
-		// If it is a panic or Goexit from certain contexts, print stack trace.
-		if _, ok := abort.(*Panic); ok || shouldPrintStack(abort.Stack()) {
-			print("\n", abort.String())
-		}
+	if ok && abort == nil {
+		stage.pass()
+		t.Wait(name)
+		return
+	}
+
+	// Fail the stage, if it had not been marked as such, yet.
+	if stage.failed.TrySet() {
+		defer stage.wg.Done()
+	}
+
+	// If it did not terminate, just abort the test.
+	if !ok {
 		t.FailNow()
 	}
 
-	stage.pass()
-	t.Wait(name)
+	// If it is a panic or Goexit from certain contexts, print stack trace.
+	if _, ok := abort.(*Panic); ok || shouldPrintStack(abort.Stack()) {
+		print("\n", abort.String())
+	}
+	t.FailNow()
 }
 
 func shouldPrintStack(stack string) bool {

pkg/test/concurrent_external_test.go

@@ -15,6 +15,7 @@
 package test_test
 
 import (
+	"context"
 	"fmt"
 	"strconv"
 	"sync"
@@ -50,20 +51,34 @@ func TestConcurrentT_Wait(t *testing.T) {
 		})
 		ctxtest.AssertTerminates(t, timeout, func() { ct.Wait("known") })
 	})
+
+	t.Run("context expiry", func(t *testing.T) {
+		ctxtest.AssertTerminates(t, timeout, func() {
+			test.AssertFatal(t, func(t test.T) {
+				ctx, cancel := context.WithCancel(context.Background())
+				cancel()
+				test.NewConcurrentCtx(t, ctx).Stage("", func(test.ConcT) {
+					time.Sleep(timeout)
+				})
+			})
+		})
+	})
 }
 
 func TestConcurrentT_FailNow(t *testing.T) {
-	var ct *test.ConcurrentT
+	t.Run("idempotence", func(t *testing.T) {
+		var ct *test.ConcurrentT
 
-	// Test that NewConcurrent.FailNow() calls T.FailNow().
-	test.AssertFatal(t, func(t test.T) {
-		ct = test.NewConcurrent(t)
-		ct.FailNow()
-	})
+		// Test that NewConcurrent.FailNow() calls T.FailNow().
+		test.AssertFatal(t, func(t test.T) {
+			ct = test.NewConcurrent(t)
+			ct.FailNow()
+		})
 
-	// Test that after that, FailNow() calls runtime.Goexit().
-	assert.True(t, test.CheckGoexit(ct.FailNow),
-		"redundant FailNow() must call runtime.Goexit()")
+		// Test that after that, FailNow() calls runtime.Goexit().
+		assert.True(t, test.CheckGoexit(ct.FailNow),
+			"redundant FailNow() must call runtime.Goexit()")
+	})
 
 	t.Run("hammer", func(t *testing.T) {
 		const parallel = 12

pkg/test/goexit.go

@@ -15,6 +15,7 @@
 package test
 
 import (
+	"context"
 	"fmt"
 	"runtime/debug"
 	"strings"
@@ -64,10 +65,11 @@ func (g Goexit) String() string {
 	return "runtime.Goexit:\n\n" + g.Stack()
 }
 
-// CheckAbort tests whether a supplied function is aborted early using panic()
-// or runtime.Goexit(). Returns a descriptor of the termination cause or nil if
-// it terminated normally.
-func CheckAbort(function func()) (abort Abort) {
+// CheckAbortCtx tests whether a supplied function terminates within a context,
+// and whether it is aborted early using panic() or runtime.Goexit(). Returns
+// whether the function terminated before the expiry of the context and if so, a
+//  descriptor of the termination cause or nil if it terminated normally.
+func CheckAbortCtx(ctx context.Context, function func()) (abort Abort, ok bool) {
 	done := make(chan struct{})
 
 	goexit := true  // Whether runtime.Goexit occurred.
@@ -103,20 +105,30 @@ func CheckAbort(function func()) (abort Abort) {
 		goexit = false
 	}()
 
-	<-done
-
-	// Concatenate the inner call stack of the failure (which starts at the
-	// goroutine instantiation) with the goroutine that is calling CheckAbort.
-	if goexit || aborted {
-		base.stack += "\n" + getStack(true, 1, 0)
+	select {
+	case <-ctx.Done():
+		return nil, false
+	case <-done:
+		ok = true
+		// Concatenate the inner call stack of the failure (which starts at the
+		// goroutine instantiation) with the goroutine that is calling CheckAbort.
+		if goexit || aborted {
+			base.stack += "\n" + getStack(true, 1, 0)
+		}
+
+		if goexit {
+			abort = &Goexit{base}
+		} else if aborted {
+			abort = &Panic{base, recovered}
+		}
+		return
 	}
+}
 
-	if goexit {
-		abort = &Goexit{base}
-	} else if aborted {
-		abort = &Panic{base, recovered}
-	}
-	return
+// CheckAbort calls CheckAbortCtx with context.Background.
+func CheckAbort(function func()) Abort {
+	abort, _ := CheckAbortCtx(context.Background(), function)
+	return abort
 }
 
 // getStack retrieves the current call stack as text, and optionally removes the