ktesting: fix vmodule support

ktesting/helper_test.go

@@ -0,0 +1,17 @@
+/*
+Copyright 2025 The Kubernetes Authors.
+
+SPDX-License-Identifier: Apache-2.0
+*/
+
+package ktesting_test
+
+import (
+	"k8s.io/klog/v2"
+)
+
+func callDepthHelper(logger klog.Logger, msg string) {
+	helper, logger := logger.WithCallStackHelper()
+	helper()
+	logger.Info(msg)
+}

ktesting/main_test.go

@@ -0,0 +1,19 @@
+/*
+Copyright 2025 The Kubernetes Authors.
+
+SPDX-License-Identifier: Apache-2.0
+*/
+
+package ktesting_test
+
+import (
+	"flag"
+	"testing"
+
+	_ "k8s.io/klog/v2/ktesting/init"
+)
+
+func TestMain(m *testing.M) {
+	flag.Parse()
+	m.Run()
+}

ktesting/testinglogger.go

@@ -307,7 +307,7 @@ func (l tlogger) Info(level int, msg string, kvList ...interface{}) {
 }
 
 func (l tlogger) Enabled(level int) bool {
-	return l.shared.config.vstate.Enabled(verbosity.Level(level), 1)
+	return l.shared.config.vstate.Enabled(verbosity.Level(level), l.shared.callDepth+1)
 }
 
 func (l tlogger) Error(err error, msg string, kvList ...interface{}) {

ktesting/testinglogger_test.go

@@ -12,8 +12,10 @@ import (
 	"errors"
 	"flag"
 	"fmt"
+	"os/exec"
 	"regexp"
 	"runtime"
+	"strings"
 	"sync"
 	"testing"
 	"time"
@@ -136,9 +138,36 @@ func TestInfo(t *testing.T) {
 	}
 }
 
-func TestCallDepth(t *testing.T) {
-	logger := ktesting.NewLogger(t, ktesting.NewConfig())
+// TestCallDepthOutput produces output which gets checked by TestCallDepthVerify.
+func TestCallDepthOutput(t *testing.T) {
+	logger := ktesting.NewLogger(t, ktesting.DefaultConfig)
 	logger.Info("hello world")
+	logger.V(1).Info("you shouldn't see this with -testing.v=0")
+	callDepthHelper(logger.V(1), "you should see this with -testing.v=0 -testing.vmodule=helper_test=1")
+}
+
+// TestCallDepthVerify runs TestCallDepth with appropriate flags and checks the output.
+//
+// Invoking `go test` is necessary because we want to verify that it correctly unwinds the stack,
+// which means that we have to let it print output. We cannot intercept that log output from
+// within a test.
+func TestCallDepthVerify(t *testing.T) {
+	cmd, args := "go", "test -v -run=TestCallDepthOutput k8s.io/klog/v2/ktesting -args -testing.v=0 -testing.vmodule=helper_test=1"
+	output, err := exec.Command("go", strings.Split(args, " ")...).CombinedOutput()
+	if err != nil {
+		t.Fatalf("failed to %s %s: %v", cmd, args, err)
+	}
+	t.Log("Got output:\n", string(output))
+
+	expect := `(?m)^[[:space:]]*testinglogger_test.go:.*hello world$
+^[[:space:]]*testinglogger_test.go:.*you should see this`
+	matched, err := regexp.MatchString(expect, string(output))
+	if err != nil {
+		t.Fatalf("failed to parse regexp: %v\n\n%s", err, expect)
+	}
+	if !matched {
+		t.Fatalf("expected output\n%s\n\nto match regexp\n%s", string(output), expect)
+	}
 }
 
 type logToBuf struct {