1 files changed, 25 insertions, 0 deletions
diff --git a/dom/heapsnapshot/tests/unit/test_census_diff_02.js b/dom/heapsnapshot/tests/unit/test_census_diff_02.js
new file mode 100644
index 000000000..169e3f036
--- /dev/null
+++ b/dom/heapsnapshot/tests/unit/test_census_diff_02.js
@@ -0,0 +1,25 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Test diffing census reports of breakdown by "count".
+
+const BREAKDOWN = { by: "count", count: true, bytes: true };
+
+const REPORT1 = {
+  "count": 10,
+  "bytes": 100,
+};
+
+const REPORT2 = {
+  "count": 11,
+  "bytes": 110,
+};
+
+const EXPECTED = {
+  "count": 1,
+  "bytes": 10,
+};
+
+function run_test() {
+  assertDiff(BREAKDOWN, REPORT1, REPORT2, EXPECTED);
+}