1 files changed, 33 insertions, 0 deletions
diff --git a/src/runtime/lockrank_test.go b/src/runtime/lockrank_test.go
new file mode 100644
index 0000000..dd99eb4
--- /dev/null
+++ b/src/runtime/lockrank_test.go
@@ -0,0 +1,33 @@
+// Copyright 2022 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 runtime_test
+
+import (
+	"bytes"
+	"internal/testenv"
+	"os"
+	"os/exec"
+	"testing"
+)
+
+// Test that the generated code for the lock rank graph is up-to-date.
+func TestLockRankGenerated(t *testing.T) {
+	testenv.MustHaveGoRun(t)
+	cmd := testenv.CleanCmdEnv(testenv.Command(t, testenv.GoToolPath(t), "run", "mklockrank.go"))
+	want, err := cmd.Output()
+	if err != nil {
+		if ee, ok := err.(*exec.ExitError); ok && len(ee.Stderr) > 0 {
+			t.Fatalf("%v: %v\n%s", cmd, err, ee.Stderr)
+		}
+		t.Fatalf("%v: %v", cmd, err)
+	}
+	got, err := os.ReadFile("lockrank.go")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(want, got) {
+		t.Fatalf("lockrank.go is out of date. Please run go generate.")
+	}
+}