1 files changed, 37 insertions, 0 deletions
diff --git a/dom/heapsnapshot/tests/unit/test_countToBucketBreakdown_01.js b/dom/heapsnapshot/tests/unit/test_countToBucketBreakdown_01.js
new file mode 100644
index 000000000..e89048c33
--- /dev/null
+++ b/dom/heapsnapshot/tests/unit/test_countToBucketBreakdown_01.js
@@ -0,0 +1,37 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
+
+// Test that we can turn a breakdown with { by: "count" } leaves into a
+// breakdown with { by: "bucket" } leaves.
+
+const COUNT = { by: "count", count: true, bytes: true };
+const BUCKET = { by: "bucket" };
+
+const BREAKDOWN = {
+  by: "coarseType",
+  objects: { by: "objectClass", then: COUNT, other: COUNT },
+  strings: COUNT,
+  scripts: {
+    by: "filename",
+    then: { by: "internalType", then: COUNT },
+    noFilename: { by: "internalType", then: COUNT },
+  },
+  other: { by: "internalType", then: COUNT },
+};
+
+const EXPECTED = {
+  by: "coarseType",
+  objects: { by: "objectClass", then: BUCKET, other: BUCKET },
+  strings: BUCKET,
+  scripts: {
+    by: "filename",
+    then: { by: "internalType", then: BUCKET },
+    noFilename: { by: "internalType", then: BUCKET },
+  },
+  other: { by: "internalType", then: BUCKET },
+};
+
+function run_test() {
+  assertCountToBucketBreakdown(BREAKDOWN, EXPECTED);
+}