feat(safety): added NoGoRoutineLeak assertion

fredbi · fredbi · commit 6276826a5eab · 2026-02-08T13:16:10.000+01:00
Signed-off-by: Frederic BIDON &lt;fredbi@yahoo.com&gt;
diff --git a/internal/assertions/safety.go b/internal/assertions/safety.go
@@ -0,0 +1,64 @@
+// SPDX-FileCopyrightText: Copyright 2025 go-swagger maintainers
+// SPDX-License-Identifier: Apache-2.0
+
+package assertions
+
+import (
+	"context"
+
+	"github.com/go-openapi/testify/v2/internal/leak"
+)
+
+// NoGoRoutineLeak ensures that no goroutine did leak from inside the tested function.
+//
+// NOTE: only the go routines spawned from inside the tested function are checked for leaks.
+// No filter or configuration is needed to exclude "known go routines".
+//
+// Resource cleanup should be done inside the tested function, and not using [testing.T.Cleanup],
+// as t.Cleanup is called after the leak check.
+//
+// # Edge cases
+//
+//   - if the tested function panics leaving behind leaked goroutines, these are detected.
+//   - if the tested function calls runtime.Goexit (e.g. from [testing.T.FailNow]) leaving behind leaked goroutines,
+//     these are detected.
+//   - if a panic occurs in one of the leaked go routines, it cannot be recovered with certainty and
+//     the calling program will usually panic.
+//
+// # Concurrency
+//
+// [NoGoRoutineLeak] may be used safely in parallel tests.
+//
+// # Usage
+//
+//	NoGoRoutineLeak(t, func() {
+//		...
+//	},
+//	"should not leak any go routine",
+//	)
+//
+// # Examples
+//
+//	success: func() {}
+func NoGoRoutineLeak(t T, tested func(), msgAndArgs ...any) bool {
+	// Domain: safety
+	if h, ok := t.(H); ok {
+		h.Helper()
+	}
+
+	var ctx context.Context
+	c, ok := t.(contextualizer)
+	if ok {
+		ctx = c.Context()
+	}
+	if ctx == nil {
+		ctx = context.Background()
+	}
+
+	signature := leak.Leaked(ctx, tested)
+	if signature == "" {
+		return true
+	}
+
+	return Fail(t, "found leaked go routines: "+signature, msgAndArgs...)
+}
diff --git a/internal/assertions/safety_test.go b/internal/assertions/safety_test.go
@@ -0,0 +1,51 @@
+// SPDX-FileCopyrightText: Copyright 2025 go-swagger maintainers
+// SPDX-License-Identifier: Apache-2.0
+
+package assertions
+
+import (
+	"sync"
+	"testing"
+)
+
+func TestNoGoRoutineLeak_Success(t *testing.T) {
+	mockT := new(mockT)
+
+	result := NoGoRoutineLeak(mockT, func() {
+		// Clean function — no goroutines spawned.
+	})
+
+	if !result {
+		t.Error("expected NoGoRoutineLeak to return true for clean function")
+	}
+	if mockT.failed {
+		t.Error("expected no failure for clean function")
+	}
+}
+
+func TestNoGoRoutineLeak_Failure(t *testing.T) {
+	blocker := make(chan struct{})
+	var wg sync.WaitGroup
+
+	t.Cleanup(func() {
+		close(blocker)
+		wg.Wait()
+	})
+
+	mockT := new(mockT)
+
+	wg.Add(1)
+	result := NoGoRoutineLeak(mockT, func() {
+		go func() {
+			defer wg.Done()
+			<-blocker // leaked: blocks until cleanup
+		}()
+	})
+
+	if result {
+		t.Error("expected NoGoRoutineLeak to return false for leaking function")
+	}
+	if !mockT.failed {
+		t.Error("expected failure to be reported for leaking function")
+	}
+}
