1 files changed, 64 insertions, 0 deletions
diff --git a/devtools/shared/heapsnapshot/tests/xpcshell/test_HeapAnalyses_takeCensusDiff_02.js b/devtools/shared/heapsnapshot/tests/xpcshell/test_HeapAnalyses_takeCensusDiff_02.js
new file mode 100644
index 0000000000..d5d988f78f
--- /dev/null
+++ b/devtools/shared/heapsnapshot/tests/xpcshell/test_HeapAnalyses_takeCensusDiff_02.js
@@ -0,0 +1,64 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
+
+// Test that the HeapAnalyses{Client,Worker} can take diffs between censuses as
+// inverted trees.
+
+const BREAKDOWN = {
+  by: "coarseType",
+  objects: {
+    by: "objectClass",
+    then: { by: "count", count: true, bytes: true },
+    other: { by: "count", count: true, bytes: true },
+  },
+  scripts: {
+    by: "internalType",
+    then: { by: "count", count: true, bytes: true },
+  },
+  strings: {
+    by: "internalType",
+    then: { by: "count", count: true, bytes: true },
+  },
+  other: {
+    by: "internalType",
+    then: { by: "count", count: true, bytes: true },
+  },
+  domNode: {
+    by: "descriptiveType",
+    then: { by: "count", count: true, bytes: true },
+  },
+};
+
+add_task(async function () {
+  const firstSnapshotFilePath = saveNewHeapSnapshot();
+  const secondSnapshotFilePath = saveNewHeapSnapshot();
+
+  const client = new HeapAnalysesClient();
+  await client.readHeapSnapshot(firstSnapshotFilePath);
+  await client.readHeapSnapshot(secondSnapshotFilePath);
+
+  ok(true, "Should have read both heap snapshot files");
+
+  const { delta } = await client.takeCensusDiff(
+    firstSnapshotFilePath,
+    secondSnapshotFilePath,
+    { breakdown: BREAKDOWN }
+  );
+
+  const { delta: deltaTreeNode } = await client.takeCensusDiff(
+    firstSnapshotFilePath,
+    secondSnapshotFilePath,
+    { breakdown: BREAKDOWN },
+    { asInvertedTreeNode: true }
+  );
+
+  // Have to manually set these because symbol properties aren't structured
+  // cloned.
+  delta[CensusUtils.basisTotalBytes] = deltaTreeNode.totalBytes;
+  delta[CensusUtils.basisTotalCount] = deltaTreeNode.totalCount;
+
+  compareCensusViewData(BREAKDOWN, delta, deltaTreeNode, { invert: true });
+
+  client.destroy();
+});