diff --git a/internal/bundler/bundler_test.go b/internal/bundler/bundler_test.go
index 84542dc395e..a817e5831a1 100644
--- a/internal/bundler/bundler_test.go
+++ b/internal/bundler/bundler_test.go
@@ -31,6 +31,7 @@ func es(version int) compat.Feature {
 }
 
 func assertEqual(t *testing.T, a interface{}, b interface{}) {
+	t.Helper()
 	if a != b {
 		stringA := fmt.Sprintf("%v", a)
 		stringB := fmt.Sprintf("%v", b)
@@ -43,6 +44,7 @@ func assertEqual(t *testing.T, a interface{}, b interface{}) {
 }
 
 func assertLog(t *testing.T, msgs []logger.Msg, expected string) {
+	t.Helper()
 	text := ""
 	for _, msg := range msgs {
 		text += msg.String(logger.StderrOptions{}, logger.TerminalInfo{})
@@ -76,8 +78,10 @@ type suite struct {
 }
 
 func (s *suite) expectBundled(t *testing.T, args bundled) {
+	t.Helper()
 	testName := t.Name()
 	t.Run("", func(t *testing.T) {
+		t.Helper()
 		fs := fs.MockFS(args.files)
 		args.options.ExtensionOrder = []string{".tsx", ".ts", ".jsx", ".js", ".json"}
 		if args.options.AbsOutputFile != "" {
@@ -129,6 +133,7 @@ var globalSuites map[*suite]bool
 var globalUpdateSnapshots bool
 
 func (s *suite) compareSnapshot(t *testing.T, testName string, generated string) {
+	t.Helper()
 	// Initialize the test suite during the first test
 	s.mutex.Lock()
 	defer s.mutex.Unlock()
diff --git a/internal/fs/fs_test.go b/internal/fs/fs_test.go
index fe7f418dd14..1759edc4e27 100644
--- a/internal/fs/fs_test.go
+++ b/internal/fs/fs_test.go
@@ -66,7 +66,9 @@ func TestRel(t *testing.T) {
 	fs := MockFS(map[string]string{})
 
 	expect := func(a string, b string, c string) {
+		t.Helper()
 		t.Run(fmt.Sprintf("Rel(%q, %q) == %q", a, b, c), func(t *testing.T) {
+			t.Helper()
 			rel, ok := fs.Rel(a, b)
 			if !ok {
 				t.Fatalf("!ok")
diff --git a/internal/lexer/lexer_test.go b/internal/lexer/lexer_test.go
index ff56acdadfc..4389ea0f7a7 100644
--- a/internal/lexer/lexer_test.go
+++ b/internal/lexer/lexer_test.go
@@ -12,6 +12,7 @@ import (
 )
 
 func assertEqualStrings(t *testing.T, a string, b string) {
+	t.Helper()
 	pretty := func(text string) string {
 		builder := strings.Builder{}
 		builder.WriteRune('"')
@@ -36,7 +37,9 @@ func lexToken(t *testing.T, contents string) T {
 }
 
 func expectLexerError(t *testing.T, contents string, expected string) {
+	t.Helper()
 	t.Run(contents, func(t *testing.T) {
+		t.Helper()
 		log := logger.NewDeferLog()
 		func() {
 			defer func() {
@@ -57,7 +60,9 @@ func expectLexerError(t *testing.T, contents string, expected string) {
 }
 
 func expectHashbang(t *testing.T, contents string, expected string) {
+	t.Helper()
 	t.Run(contents, func(t *testing.T) {
+		t.Helper()
 		log := logger.NewDeferLog()
 		lexer := func() Lexer {
 			defer func() {
@@ -83,7 +88,9 @@ func TestHashbang(t *testing.T) {
 }
 
 func expectIdentifier(t *testing.T, contents string, expected string) {
+	t.Helper()
 	t.Run(contents, func(t *testing.T) {
+		t.Helper()
 		log := logger.NewDeferLog()
 		lexer := func() Lexer {
 			defer func() {
@@ -120,7 +127,9 @@ func TestIdentifier(t *testing.T) {
 }
 
 func expectNumber(t *testing.T, contents string, expected float64) {
+	t.Helper()
 	t.Run(contents, func(t *testing.T) {
+		t.Helper()
 		log := logger.NewDeferLog()
 		lexer := func() Lexer {
 			defer func() {
@@ -325,7 +334,9 @@ func TestNumericLiteral(t *testing.T) {
 }
 
 func expectBigInteger(t *testing.T, contents string, expected string) {
+	t.Helper()
 	t.Run(contents, func(t *testing.T) {
+		t.Helper()
 		log := logger.NewDeferLog()
 		lexer := func() Lexer {
 			defer func() {
@@ -378,7 +389,9 @@ func TestBigIntegerLiteral(t *testing.T) {
 }
 
 func expectString(t *testing.T, contents string, expected string) {
+	t.Helper()
 	t.Run(contents, func(t *testing.T) {
+		t.Helper()
 		log := logger.NewDeferLog()
 		lexer := func() Lexer {
 			defer func() {
diff --git a/internal/parser/parser_json_test.go b/internal/parser/parser_json_test.go
index 098010d7345..f7852f5081c 100644
--- a/internal/parser/parser_json_test.go
+++ b/internal/parser/parser_json_test.go
@@ -11,7 +11,9 @@ import (
 )
 
 func expectParseErrorJSON(t *testing.T, contents string, expected string) {
+	t.Helper()
 	t.Run(contents, func(t *testing.T) {
+		t.Helper()
 		log := logger.NewDeferLog()
 		ParseJSON(log, test.SourceForTest(contents), ParseJSONOptions{})
 		msgs := log.Done()
@@ -27,7 +29,9 @@ func expectParseErrorJSON(t *testing.T, contents string, expected string) {
 // code may not be valid JSON. That's ok because esbuild always outputs JS
 // bundles, not JSON bundles.
 func expectPrintedJSON(t *testing.T, contents string, expected string) {
+	t.Helper()
 	t.Run(contents, func(t *testing.T) {
+		t.Helper()
 		log := logger.NewDeferLog()
 		expr, ok := ParseJSON(log, test.SourceForTest(contents), ParseJSONOptions{})
 		msgs := log.Done()
@@ -47,7 +51,9 @@ func expectPrintedJSON(t *testing.T, contents string, expected string) {
 }
 
 func expectPrintedJSONWithWarning(t *testing.T, contents string, warning string, expected string) {
+	t.Helper()
 	t.Run(contents, func(t *testing.T) {
+		t.Helper()
 		log := logger.NewDeferLog()
 		expr, ok := ParseJSON(log, test.SourceForTest(contents), ParseJSONOptions{})
 		msgs := log.Done()
diff --git a/internal/parser/parser_test.go b/internal/parser/parser_test.go
index e52360f73d6..59b3287542c 100644
--- a/internal/parser/parser_test.go
+++ b/internal/parser/parser_test.go
@@ -15,7 +15,9 @@ import (
 )
 
 func expectParseError(t *testing.T, contents string, expected string) {
+	t.Helper()
 	t.Run(contents, func(t *testing.T) {
+		t.Helper()
 		log := logger.NewDeferLog()
 		Parse(log, test.SourceForTest(contents), config.Options{})
 		msgs := log.Done()
@@ -28,7 +30,9 @@ func expectParseError(t *testing.T, contents string, expected string) {
 }
 
 func expectParseErrorTarget(t *testing.T, esVersion int, contents string, expected string) {
+	t.Helper()
 	t.Run(contents, func(t *testing.T) {
+		t.Helper()
 		log := logger.NewDeferLog()
 		Parse(log, test.SourceForTest(contents), config.Options{
 			UnsupportedFeatures: compat.UnsupportedFeatures(map[compat.Engine][]int{
@@ -45,7 +49,9 @@ func expectParseErrorTarget(t *testing.T, esVersion int, contents string, expect
 }
 
 func expectPrinted(t *testing.T, contents string, expected string) {
+	t.Helper()
 	t.Run(contents, func(t *testing.T) {
+		t.Helper()
 		log := logger.NewDeferLog()
 		tree, ok := Parse(log, test.SourceForTest(contents), config.Options{})
 		msgs := log.Done()
@@ -68,7 +74,9 @@ func expectPrinted(t *testing.T, contents string, expected string) {
 }
 
 func expectPrintedMangle(t *testing.T, contents string, expected string) {
+	t.Helper()
 	t.Run(contents, func(t *testing.T) {
+		t.Helper()
 		log := logger.NewDeferLog()
 		tree, ok := Parse(log, test.SourceForTest(contents), config.Options{
 			MangleSyntax: true,
@@ -91,7 +99,9 @@ func expectPrintedMangle(t *testing.T, contents string, expected string) {
 }
 
 func expectPrintedTarget(t *testing.T, esVersion int, contents string, expected string) {
+	t.Helper()
 	t.Run(contents, func(t *testing.T) {
+		t.Helper()
 		log := logger.NewDeferLog()
 		unsupportedFeatures := compat.UnsupportedFeatures(map[compat.Engine][]int{
 			compat.ES: {esVersion},
@@ -121,7 +131,9 @@ func expectPrintedTarget(t *testing.T, esVersion int, contents string, expected
 }
 
 func expectPrintedTargetStrict(t *testing.T, esVersion int, contents string, expected string) {
+	t.Helper()
 	t.Run(contents, func(t *testing.T) {
+		t.Helper()
 		log := logger.NewDeferLog()
 		tree, ok := Parse(log, test.SourceForTest(contents), config.Options{
 			UnsupportedFeatures: compat.UnsupportedFeatures(map[compat.Engine][]int{
@@ -153,7 +165,9 @@ func expectPrintedTargetStrict(t *testing.T, esVersion int, contents string, exp
 }
 
 func expectParseErrorJSX(t *testing.T, contents string, expected string) {
+	t.Helper()
 	t.Run(contents, func(t *testing.T) {
+		t.Helper()
 		log := logger.NewDeferLog()
 		Parse(log, test.SourceForTest(contents), config.Options{
 			JSX: config.JSXOptions{
@@ -170,7 +184,9 @@ func expectParseErrorJSX(t *testing.T, contents string, expected string) {
 }
 
 func expectPrintedJSX(t *testing.T, contents string, expected string) {
+	t.Helper()
 	t.Run(contents, func(t *testing.T) {
+		t.Helper()
 		log := logger.NewDeferLog()
 		tree, ok := Parse(log, test.SourceForTest(contents), config.Options{
 			JSX: config.JSXOptions{
diff --git a/internal/parser/parser_ts_test.go b/internal/parser/parser_ts_test.go
index a497846e460..43ab55a3968 100644
--- a/internal/parser/parser_ts_test.go
+++ b/internal/parser/parser_ts_test.go
@@ -12,7 +12,9 @@ import (
 )
 
 func expectParseErrorTS(t *testing.T, contents string, expected string) {
+	t.Helper()
 	t.Run(contents, func(t *testing.T) {
+		t.Helper()
 		log := logger.NewDeferLog()
 		Parse(log, test.SourceForTest(contents), config.Options{
 			TS: config.TSOptions{
@@ -29,7 +31,9 @@ func expectParseErrorTS(t *testing.T, contents string, expected string) {
 }
 
 func expectPrintedTS(t *testing.T, contents string, expected string) {
+	t.Helper()
 	t.Run(contents, func(t *testing.T) {
+		t.Helper()
 		log := logger.NewDeferLog()
 		tree, ok := Parse(log, test.SourceForTest(contents), config.Options{
 			TS: config.TSOptions{
@@ -54,7 +58,9 @@ func expectPrintedTS(t *testing.T, contents string, expected string) {
 }
 
 func expectParseErrorTSX(t *testing.T, contents string, expected string) {
+	t.Helper()
 	t.Run(contents, func(t *testing.T) {
+		t.Helper()
 		log := logger.NewDeferLog()
 		Parse(log, test.SourceForTest(contents), config.Options{
 			TS: config.TSOptions{
@@ -74,7 +80,9 @@ func expectParseErrorTSX(t *testing.T, contents string, expected string) {
 }
 
 func expectPrintedTSX(t *testing.T, contents string, expected string) {
+	t.Helper()
 	t.Run(contents, func(t *testing.T) {
+		t.Helper()
 		log := logger.NewDeferLog()
 		tree, ok := Parse(log, test.SourceForTest(contents), config.Options{
 			TS: config.TSOptions{
diff --git a/internal/printer/printer_test.go b/internal/printer/printer_test.go
index d99673b97d3..d0578bb4b0b 100644
--- a/internal/printer/printer_test.go
+++ b/internal/printer/printer_test.go
@@ -13,13 +13,16 @@ import (
 )
 
 func assertEqual(t *testing.T, a interface{}, b interface{}) {
+	t.Helper()
 	if a != b {
 		t.Fatalf("%s != %s", a, b)
 	}
 }
 
 func expectPrintedCommon(t *testing.T, name string, contents string, expected string, options PrintOptions) {
+	t.Helper()
 	t.Run(name, func(t *testing.T) {
+		t.Helper()
 		log := logger.NewDeferLog()
 		tree, ok := parser.Parse(log, test.SourceForTest(contents), config.Options{})
 		msgs := log.Done()
@@ -40,22 +43,26 @@ func expectPrintedCommon(t *testing.T, name string, contents string, expected st
 }
 
 func expectPrinted(t *testing.T, contents string, expected string) {
+	t.Helper()
 	expectPrintedCommon(t, contents, contents, expected, PrintOptions{})
 }
 
 func expectPrintedMinify(t *testing.T, contents string, expected string) {
+	t.Helper()
 	expectPrintedCommon(t, contents+" [minified]", contents, expected, PrintOptions{
 		RemoveWhitespace: true,
 	})
 }
 
 func expectPrintedMangle(t *testing.T, contents string, expected string) {
+	t.Helper()
 	expectPrintedCommon(t, contents+" [minified]", contents, expected, PrintOptions{
 		MangleSyntax: true,
 	})
 }
 
 func expectPrintedTarget(t *testing.T, esVersion int, contents string, expected string) {
+	t.Helper()
 	expectPrintedCommon(t, contents, contents, expected, PrintOptions{
 		UnsupportedFeatures: compat.UnsupportedFeatures(map[compat.Engine][]int{
 			compat.ES: {esVersion},
@@ -64,6 +71,7 @@ func expectPrintedTarget(t *testing.T, esVersion int, contents string, expected
 }
 
 func expectPrintedTargetMinify(t *testing.T, esVersion int, contents string, expected string) {
+	t.Helper()
 	expectPrintedCommon(t, contents+" [minified]", contents, expected, PrintOptions{
 		UnsupportedFeatures: compat.UnsupportedFeatures(map[compat.Engine][]int{
 			compat.ES: {esVersion},
@@ -73,6 +81,7 @@ func expectPrintedTargetMinify(t *testing.T, esVersion int, contents string, exp
 }
 
 func expectPrintedTargetMangle(t *testing.T, esVersion int, contents string, expected string) {
+	t.Helper()
 	expectPrintedCommon(t, contents+" [minified]", contents, expected, PrintOptions{
 		UnsupportedFeatures: compat.UnsupportedFeatures(map[compat.Engine][]int{
 			compat.ES: {esVersion},
diff --git a/internal/test/util.go b/internal/test/util.go
index a14e2388c1c..fe6d1ec2c3f 100644
--- a/internal/test/util.go
+++ b/internal/test/util.go
@@ -7,6 +7,7 @@ import (
 )
 
 func AssertEqual(t *testing.T, a interface{}, b interface{}) {
+	t.Helper()
 	if a != b {
 		t.Fatalf("%s != %s", a, b)
 	}