diff --git a/internal/fxreflect/stack_120_test.go b/internal/fxreflect/stack_120_test.go
new file mode 100644
index 000000000..4c2e118c0
--- /dev/null
+++ b/internal/fxreflect/stack_120_test.go
@@ -0,0 +1,30 @@
+//go:build !go1.21
+// +build !go1.21
+
+package fxreflect
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestDeepStack(t *testing.T) {
+	t.Run("nest", func(t *testing.T) {
+		// Introduce a few frames.
+		frames := func() []Frame {
+			return func() []Frame {
+				return CallerStack(0, 0)
+			}()
+		}()
+
+		require.True(t, len(frames) > 3, "expected at least three frames")
+		for i, name := range []string{"func1.1.1", "func1.1", "func1"} {
+			f := frames[i]
+			assert.Equal(t, "go.uber.org/fx/internal/fxreflect.TestDeepStack."+name, f.Function)
+			assert.Contains(t, f.File, "internal/fxreflect/stack_120_test.go")
+			assert.NotZero(t, f.Line)
+		}
+	})
+}
diff --git a/internal/fxreflect/stack_121_test.go b/internal/fxreflect/stack_121_test.go
new file mode 100644
index 000000000..e955bba28
--- /dev/null
+++ b/internal/fxreflect/stack_121_test.go
@@ -0,0 +1,30 @@
+//go:build go1.21
+// +build go1.21
+
+package fxreflect
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestDeepStack(t *testing.T) {
+	t.Run("nest", func(t *testing.T) {
+		// Introduce a few frames.
+		frames := func() []Frame {
+			return func() []Frame {
+				return CallerStack(0, 0)
+			}()
+		}()
+
+		require.True(t, len(frames) > 3, "expected at least three frames")
+		for i, name := range []string{"func1.TestDeepStack.func1.1.func2", "func1.1", "func1"} {
+			f := frames[i]
+			assert.Equal(t, "go.uber.org/fx/internal/fxreflect.TestDeepStack."+name, f.Function)
+			assert.Contains(t, f.File, "internal/fxreflect/stack_121_test.go")
+			assert.NotZero(t, f.Line)
+		}
+	})
+}
diff --git a/internal/fxreflect/stack_test_120.go b/internal/fxreflect/stack_test_120.go
deleted file mode 100644
index c1aa64c64..000000000
--- a/internal/fxreflect/stack_test_120.go
+++ /dev/null
@@ -1,28 +0,0 @@
-//go:build !go1.21
-// +build !go1.21
-
-package fxreflect
-
-import (
-	"testing"
-
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-)
-
-func TestDeepStack(t *testing.T) {
-	// Introduce a few frames.
-	frames := func() []Frame {
-		return func() []Frame {
-			return CallerStack(0, 0)
-		}()
-	}()
-
-	require.True(t, len(frames) > 3, "expected at least three frames")
-	for i, name := range []string{"func2.1.1", "func2.1", "func2"} {
-		f := frames[i]
-		assert.Equal(t, "go.uber.org/fx/internal/fxreflect.TestStack."+name, f.Function)
-		assert.Contains(t, f.File, "internal/fxreflect/stack_test.go")
-		assert.NotZero(t, f.Line)
-	}
-}
diff --git a/internal/fxreflect/stack_test_121.go b/internal/fxreflect/stack_test_121.go
deleted file mode 100644
index 40b03a2fe..000000000
--- a/internal/fxreflect/stack_test_121.go
+++ /dev/null
@@ -1,28 +0,0 @@
-//go:build go1.21
-// +build go1.21
-
-package fxreflect
-
-import (
-	"testing"
-
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-)
-
-func TestDeepStack(t *testing.T) {
-	// Introduce a few frames.
-	frames := func() []Frame {
-		return func() []Frame {
-			return CallerStack(0, 0)
-		}()
-	}()
-
-	require.True(t, len(frames) > 3, "expected at least three frames")
-	for i, name := range []string{"func2.TestStack.func2.1.func2", "func2.1", "func2"} {
-		f := frames[i]
-		assert.Equal(t, "go.uber.org/fx/internal/fxreflect.TestStack."+name, f.Function)
-		assert.Contains(t, f.File, "internal/fxreflect/stack_test.go")
-		assert.NotZero(t, f.Line)
-	}
-}