1 files changed, 49 insertions, 0 deletions
diff --git a/devtools/shared/heapsnapshot/tests/xpcshell/test_DominatorTreeNode_getNodeByIdAlongPath_01.js b/devtools/shared/heapsnapshot/tests/xpcshell/test_DominatorTreeNode_getNodeByIdAlongPath_01.js
new file mode 100644
index 0000000000..be1f210c3e
--- /dev/null
+++ b/devtools/shared/heapsnapshot/tests/xpcshell/test_DominatorTreeNode_getNodeByIdAlongPath_01.js
@@ -0,0 +1,49 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+"use strict";
+
+// Test that we can find the node with the given id along the specified path.
+
+const node3000 = makeTestDominatorTreeNode({ nodeId: 3000 });
+
+const node2000 = makeTestDominatorTreeNode({ nodeId: 2000 }, [
+  makeTestDominatorTreeNode({}),
+  node3000,
+  makeTestDominatorTreeNode({}),
+]);
+
+const node1000 = makeTestDominatorTreeNode({ nodeId: 1000 }, [
+  makeTestDominatorTreeNode({}),
+  node2000,
+  makeTestDominatorTreeNode({}),
+]);
+
+const tree = node1000;
+
+const path = [1000, 2000, 3000];
+
+const tests = [
+  { id: 1000, expected: node1000 },
+  { id: 2000, expected: node2000 },
+  { id: 3000, expected: node3000 },
+];
+
+function run_test() {
+  for (const { id, expected } of tests) {
+    const actual = DominatorTreeNode.getNodeByIdAlongPath(id, tree, path);
+    equal(actual, expected, `We should have got the node with id = ${id}`);
+  }
+
+  equal(
+    null,
+    DominatorTreeNode.getNodeByIdAlongPath(999999999999, tree, path),
+    "null is returned for nodes that are not even in the tree"
+  );
+
+  const lastNodeId = tree.children[tree.children.length - 1].nodeId;
+  equal(
+    null,
+    DominatorTreeNode.getNodeByIdAlongPath(lastNodeId, tree, path),
+    "null is returned for nodes that are not along the path"
+  );
+}