ktesting: more flexible WithContext

As a special case, WithContext preserved the logger in the parent context. But
for the upcoming usage of WithValue to store a Kubernetes client it is
important to also preserve access to other values.

test/utils/ktesting/tcontext.go

@@ -26,7 +26,6 @@ import (
 	"testing/synctest"
 	"time"
 
-	"github.com/go-logr/logr"
 	"github.com/onsi/gomega"
 
 	apiextensions "k8s.io/apiextensions-apiserver/pkg/client/clientset/clientset"
@@ -333,15 +332,12 @@ func run(tCtx TContext, name string, syncTest bool, cb func(tCtx TContext)) bool
 //	   tCtx := ktesting.WithContext(tCtx, ctx)
 //	   ...
 //
-// This is important because the Context in the callback could have
-// a different deadline than in the parent TContext.
+// Cancellation and deadline are determined by the new context.
+// Values are looked up first in the new context, then the old one.
+// In other words, values set previous via WithValue are still
+// available.
 func (tCtx TContext) WithContext(ctx context.Context) TContext {
-	logger := tCtx.Logger()
-	tCtx.Context = ctx
-	if _, err := logr.FromContext(ctx); err != nil {
-		// Keep using the logger from the parent context.
-		tCtx = tCtx.WithLogger(logger)
-	}
+	tCtx.Context = &chainContext{Context: ctx, previousCtx: tCtx.Context}
 	return tCtx
 }
 
@@ -351,6 +347,18 @@ func (tCtx TContext) WithValue(key, val any) TContext {
 	return tCtx.WithContext(ctx)
 }
 
+type chainContext struct {
+	context.Context
+	previousCtx context.Context
+}
+
+func (ctx *chainContext) Value(key any) any {
+	if val := ctx.Context.Value(key); val != nil {
+		return val
+	}
+	return ctx.previousCtx.Value(key)
+}
+
 // TContext implements [context.Context], [testing.TB] and some additional
 // methods. [TContext] is the public pointer type for referencing a TC.
 // Variables are usually called tCtx. To ensure that test code does not

test/utils/ktesting/tcontext_test.go

@@ -17,6 +17,7 @@ limitations under the License.
 package ktesting_test
 
 import (
+	"context"
 	"sync"
 	"testing"
 	"testing/synctest"
@@ -208,3 +209,16 @@ func TestWithNamespace(t *testing.T) {
 	tCtxWithNamespace := tCtx.WithNamespace(namespace)
 	tCtx.Expect(tCtxWithNamespace.Namespace()).To(gomega.Equal(namespace))
 }
+
+func TestWithContext(t *testing.T) {
+	tCtx := ktesting.Init(t)
+	tCtx.Cancel("done")
+	tCtx = tCtx.WithValue("foo", "bar")
+	deadline := time.Now().Add(-time.Minute)
+	ctx, cancel := context.WithDeadline(context.Background(), deadline)
+	defer cancel()
+	newCtx := tCtx.WithContext(ctx)
+	tCtx.Expect(context.Cause(tCtx)).To(gomega.MatchError(gomega.ContainSubstring("done")))
+	tCtx.Expect(newCtx.Err()).To(gomega.MatchError(context.DeadlineExceeded))
+	tCtx.Expect(newCtx.Value("foo")).To(gomega.Equal("bar"))
+}