Due to bug 652494, browser_inspector_breadcrumbs.js should be failing due to an uncaught JS exception, but is not: nodes[cursor] is undefined at chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js:82

How can I see this exception? I don't see any error in my terminal when I run: TEST_PATH=browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js make mochitest-browser-chrome

I haven't managed to reproduce it locally, but it appears on the build machines. For example in the Linux opt m-o log from the current tip of m-c: https://tbpl.mozilla.org/php/getParsedLog.php?id=7408578&tree=Firefox&full=1

Complete (related) log: TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | node i1111 found TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | node i22 found TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | node i2111 found TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | node i21 found TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | node i22211 found TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | node i22 found TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Node 0: Items count TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Node 0: button 2 matches TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Node 0: button 3 matches TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Node 0: button 4 matches TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Node 0: button 5 matches TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Node 0: selection matches TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Node 1: Items count TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Node 1: button 2 matches TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Node 1: button 3 matches TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Node 1: button 4 matches TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Node 1: selection matches TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Node 2: Items count TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Node 2: button 2 matches TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Node 2: button 3 matches TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Node 2: button 4 matches TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Node 2: button 5 matches TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Node 2: selection matches TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Node 3: Items count TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Node 3: button 2 matches TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Node 3: button 3 matches TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Node 3: button 4 matches TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Node 3: button 5 matches TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Node 3: selection matches TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Node 4: Items count TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Node 4: button 2 matches TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Node 4: button 3 matches TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Node 4: button 4 matches TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Node 4: button 5 matches TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Node 4: button 6 matches TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Node 4: selection matches TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Node 5: Items count TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Node 5: button 2 matches TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Node 5: button 3 matches TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Node 5: button 4 matches TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Node 5: button 5 matches TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Node 5: button 6 matches TEST-PASS | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Node 5: selection matches TEST-KNOWN-FAIL | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | [SimpleTest/SimpleTest.js, window.onerror] TEST-KNOWN-FAIL | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | [SimpleTest/SimpleTest.js, window.onerror] TEST-INFO | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Console message: [JavaScript Error: "nodes[cursor] is undefined" {file: "chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js" line: 83}] TEST-INFO | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | Console message: [JavaScript Error: "nodes[cursor] is undefined" {file: "chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js" line: 83}] INFO TEST-END | chrome://mochitests/content/browser/browser/devtools/highlighter/test/browser_inspector_breadcrumbs.js | finished in 499ms