1 files changed, 36 insertions, 0 deletions
diff --git a/src/runtime/_mkmalloc/mkmalloc_test.go b/src/runtime/_mkmalloc/mkmalloc_test.go
new file mode 100644
index 0000000000..bd15c3226a
--- /dev/null
+++ b/src/runtime/_mkmalloc/mkmalloc_test.go
@@ -0,0 +1,36 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import (
+	"bytes"
+	"os"
+	"testing"
+)
+
+func TestNoChange(t *testing.T) {
+	classes := makeClasses()
+	sizeToSizeClass := makeSizeToSizeClass(classes)
+
+	outfile := "../malloc_generated.go"
+	want, err := os.ReadFile(outfile)
+	if err != nil {
+		t.Fatal(err)
+	}
+	got := mustFormat(inline(specializedMallocConfig(classes, sizeToSizeClass)))
+	if !bytes.Equal(want, got) {
+		t.Fatalf("want:\n%s\ngot:\n%s\n", withLineNumbers(want), withLineNumbers(got))
+	}
+
+	tablefile := "../malloc_tables_generated.go"
+	wanttable, err := os.ReadFile(tablefile)
+	if err != nil {
+		t.Fatal(err)
+	}
+	gotTable := mustFormat(generateTable(sizeToSizeClass))
+	if !bytes.Equal(wanttable, gotTable) {
+		t.Fatalf("want:\n%s\ngot:\n%s\n", withLineNumbers(wanttable), withLineNumbers(gotTable))
+	}
+}