test_HeapSnapshot_getObjectNodeId_01.js

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/* Any copyright is dedicated to the Public Domain.

   http://creativecommons.org/publicdomain/zero/1.0/ */

"use strict";

// Test ChromeUtils.getObjectNodeId()

function run_test() {

  // Create a test object, which we want to analyse

  const testObject = {

    foo: {

      bar: {},

},

};

  const path = ChromeUtils.saveHeapSnapshot({ runtime: true });

  const snapshot = ChromeUtils.readHeapSnapshot(path);

  // Get the NodeId for our test object

  const objectNodeIdRoot = ChromeUtils.getObjectNodeId(testObject);

  const objectNodeIdFoo = ChromeUtils.getObjectNodeId(testObject.foo);

  const objectNodeIdBar = ChromeUtils.getObjectNodeId(testObject.foo.bar);

  // Also try to ensure that this is the right object via its retained path

  const shortestPaths = snapshot.computeShortestPaths(

    objectNodeIdRoot,

    [objectNodeIdBar],

);

  ok(shortestPaths);

  ok(shortestPaths instanceof Map);

  Assert.equal(

    shortestPaths.size,

1,

    "We get only one path between the root object and bar object"

);

  const paths = shortestPaths.get(objectNodeIdBar);

  Assert.equal(paths.length, 1, "There is only one path between root and bar");

  Assert.equal(

    paths[0].length,

2,

    "The shortest path is made of two edges: foo and bar"

);

  const [path1, path2] = paths[0];

  Assert.equal(

    path1.predecessor,

    objectNodeIdRoot,

    "The first edge goes from the root object"

);

  Assert.equal(path1.edge, "foo", "The first edge is the foo attribute");

  Assert.equal(

    path2.predecessor,

    objectNodeIdFoo,

    "The second edge goes from the foo object"

);

  Assert.equal(path2.edge, "bar", "The first edge is the bar attribute");

  do_test_finished();