1 files changed, 30 insertions, 0 deletions
diff --git a/devtools/shared/heapsnapshot/tests/xpcshell/test_DominatorTree_04.js b/devtools/shared/heapsnapshot/tests/xpcshell/test_DominatorTree_04.js
new file mode 100644
index 0000000000..2bfe46977f
--- /dev/null
+++ b/devtools/shared/heapsnapshot/tests/xpcshell/test_DominatorTree_04.js
@@ -0,0 +1,30 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
+
+// Test that we can get the retained sizes of dominator trees.
+
+function run_test() {
+  const dominatorTree = saveHeapSnapshotAndComputeDominatorTree();
+  equal(
+    typeof dominatorTree.getRetainedSize,
+    "function",
+    "getRetainedSize should be a function"
+  );
+
+  const size = dominatorTree.getRetainedSize(dominatorTree.root);
+  ok(size, "should get a size for the root");
+  equal(typeof size, "number", "retained sizes should be a number");
+  equal(Math.floor(size), size, "size should be an integer");
+  Assert.greater(size, 0, "size should be positive");
+  Assert.lessOrEqual(
+    size,
+    Math.pow(2, 64),
+    "size should be less than or equal to 2^64"
+  );
+
+  const bad = dominatorTree.getRetainedSize(1);
+  equal(bad, null, "null is returned for unknown node ids");
+
+  do_test_finished();
+}