1 files changed, 43 insertions, 0 deletions
diff --git a/dom/heapsnapshot/tests/unit/test_census-tree-node-10.js b/dom/heapsnapshot/tests/unit/test_census-tree-node-10.js
new file mode 100644
index 000000000..b7798f23f
--- /dev/null
+++ b/dom/heapsnapshot/tests/unit/test_census-tree-node-10.js
@@ -0,0 +1,43 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
+
+/**
+ * Test when multiple leaves in the census report map to the same node in an
+ * inverted CensusReportTree.
+ */
+
+function run_test() {
+  const BREAKDOWN = {
+    by: "coarseType",
+    objects: {
+      by: "objectClass",
+      then: { by: "count", count: true, bytes: true },
+    },
+    other: {
+      by: "internalType",
+      then: { by: "count", count: true, bytes: true },
+    },
+    strings: { by: "count", count: true, bytes: true },
+    scripts: { by: "count", count: true, bytes: true },
+  };
+
+  const REPORT = {
+    objects: {
+      Array: { count: 1, bytes: 10 },
+    },
+    other: {
+      Array: { count: 1, bytes: 10 },
+    },
+    strings: { count: 0, bytes: 0 },
+    scripts: { count: 0, bytes: 0 },
+  };
+
+  const node = censusReportToCensusTreeNode(BREAKDOWN, REPORT, { invert: true });
+
+  equal(node.children[0].name, "Array");
+  equal(node.children[0].reportLeafIndex.size, 2);
+  dumpn(`node.children[0].reportLeafIndex = ${[...node.children[0].reportLeafIndex]}`);
+  ok(node.children[0].reportLeafIndex.has(2));
+  ok(node.children[0].reportLeafIndex.has(6));
+}