[tbb-commits] [tor-browser-bundle-testsuite/master] Fix performance-observer test

[gk at torproject.org]

commit 1b30b27ffd9af1ef9a0a6bd81e3c1247a7e96637
Author: Alex Catarineu <acat at torproject.org>
Date:   Mon May 18 08:56:21 2020 +0200

    Fix performance-observer test
---
 TBBTestSuite/TestSuite/BrowserBundleTests.pm       |  7 ----
 .../tor_browser_tests/test_performance-observer.py | 38 ++++++++++++----------
 2 files changed, 21 insertions(+), 24 deletions(-)

diff --git a/TBBTestSuite/TestSuite/BrowserBundleTests.pm b/TBBTestSuite/TestSuite/BrowserBundleTests.pm
index e35e903..0bf4359 100644
--- a/TBBTestSuite/TestSuite/BrowserBundleTests.pm
+++ b/TBBTestSuite/TestSuite/BrowserBundleTests.pm
@@ -380,13 +380,6 @@ our @tests = (
         type            => 'marionette',
         descr           => 'Check that the Performance Observer API is really disabled',
         use_net         => 1,
-        # To check that the test fails when performance observer is enabled,
-        # uncomment this:
-        #prefs           => {
-        #    'dom.enable_performance_observer' => 'true',
-        #},
-        # Bug 27137: temporarily disable test
-        enable          => sub { undef },
     },
     {
         name            => 'searchengines',
diff --git a/marionette/tor_browser_tests/test_performance-observer.py b/marionette/tor_browser_tests/test_performance-observer.py
index 31c3c5f..b727a01 100644
--- a/marionette/tor_browser_tests/test_performance-observer.py
+++ b/marionette/tor_browser_tests/test_performance-observer.py
@@ -4,9 +4,6 @@
 # Setting |dom.enable_performance_observer| to |false| and testing that
 # might not be sufficient.
 
-from marionette_driver import By
-from marionette_driver.errors import MarionetteException
-
 from marionette_harness import MarionetteTestCase
 
 class Test(MarionetteTestCase):
@@ -19,18 +16,25 @@ class Test(MarionetteTestCase):
 
     def test_performance_observer(self):
 
+        def is_perf_obs_working(marionette):
+            return self.marionette.execute_async_script("""
+                let [resolve] = arguments;
+                var observer = new PerformanceObserver(function(...args) { resolve(true); });
+                observer.observe({entryTypes: ['resource', 'mark', 'measure']});
+                performance.mark("hello");
+                setTimeout(function() {
+                    resolve(false);
+                }, 2000);
+            """)
+
         with self.marionette.using_context('content'):
-            self.marionette.navigate(self.TEST_URL)
-
-            err_msg = 'performance observer is working'
-            self.assertTrue(self.marionette.execute_script("""
-                var pass = false;
-                try {
-                        var observer = new PerformanceObserver(function(list) { });
-                        observer.observe({entryTypes: ['resource', 'mark', 'measure']});
-                } catch (e) {
-                        pass = true;
-                }
-                return pass;
-                """),
-                msg=err_msg)
+            m = self.marionette
+            m.navigate(self.TEST_URL)
+            m.timeout.script = 10
+
+            # Performance observer should not work with default settings
+            self.assertFalse(is_perf_obs_working(m), 'performance observer is working')
+
+            # Performance observer should work if `privacy.resistFingerprinting = false`
+            with self.marionette.using_prefs({"privacy.resistFingerprinting": False}):
+                self.assertTrue(is_perf_obs_working(m), 'performance observer is not working')