1 files changed, 41 insertions, 0 deletions
diff --git a/src/runtime/lockrank_test.go b/src/runtime/lockrank_test.go
new file mode 100644
index 0000000..4b2fc0e
--- /dev/null
+++ b/src/runtime/lockrank_test.go
@@ -0,0 +1,41 @@
+// Copyright 2021 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 (
+	. "runtime"
+	"testing"
+)
+
+// Check that the partial order in lockPartialOrder fits within the total order
+// determined by the order of the lockRank constants.
+func TestLockRankPartialOrder(t *testing.T) {
+	for r, list := range LockPartialOrder {
+		rank := LockRank(r)
+		for _, e := range list {
+			entry := LockRank(e)
+			if entry > rank {
+				t.Errorf("lockPartialOrder row %v entry %v is inconsistent with total lock ranking order", rank, entry)
+			}
+		}
+	}
+}
+
+// Verify that partial order lists are kept sorted. This is a purely cosemetic
+// check to make manual reviews simpler. It does not affect correctness, unlike
+// the above test.
+func TestLockRankPartialOrderSortedEntries(t *testing.T) {
+	for r, list := range LockPartialOrder {
+		rank := LockRank(r)
+		var prev LockRank
+		for _, e := range list {
+			entry := LockRank(e)
+			if entry <= prev {
+				t.Errorf("Partial order for rank %v out of order: %v <= %v in %v", rank, entry, prev, list)
+			}
+			prev = entry
+		}
+	}
+}