tests: better fatal trace logic error coverage (#7959)

GoogleChrome · Apr 4, 2019 · c140802 · c140802
1 parent b8ac221
commit c140802
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Showing 2 changed files with 49 additions and 3 deletions.
diff --git a/lighthouse-core/computed/main-thread-tasks.js b/lighthouse-core/computed/main-thread-tasks.js
@@ -148,11 +148,16 @@ class MainThreadTasks {
 
   /**
    * @param {TaskNode} task
+   * @param {TaskNode|undefined} parent
    * @return {number}
    */
-  static _computeRecursiveSelfTime(task) {
+  static _computeRecursiveSelfTime(task, parent) {
+    if (parent && task.endTime > parent.endTime) {
+      throw new Error('Fatal trace logic error - child cannot end after parent');
+    }
+
     const childTime = task.children
-      .map(MainThreadTasks._computeRecursiveSelfTime)
+      .map(child => MainThreadTasks._computeRecursiveSelfTime(child, task))
       .reduce((sum, child) => sum + child, 0);
     task.duration = task.endTime - task.startTime;
     task.selfTime = task.duration - childTime;
@@ -237,7 +242,7 @@ class MainThreadTasks {
     for (const task of tasks) {
       if (task.parent) continue;
 
-      MainThreadTasks._computeRecursiveSelfTime(task);
+      MainThreadTasks._computeRecursiveSelfTime(task, undefined);
       MainThreadTasks._computeRecursiveAttributableURLs(task, [], priorTaskData);
       MainThreadTasks._computeRecursiveTaskGroup(task);
     }

diff --git a/lighthouse-core/test/computed/main-thread-tasks-test.js b/lighthouse-core/test/computed/main-thread-tasks-test.js
@@ -195,4 +195,45 @@ describe('MainResource computed artifact', () => {
       group: taskGroups.other,
     });
   });
+
+  const invalidEventSets = [
+    [
+      // TaskA overlaps with TaskB, X first
+      {ph: 'X', name: 'TaskA', pid, tid, ts: baseTs, dur: 100e3, args},
+      {ph: 'B', name: 'TaskB', pid, tid, ts: baseTs + 5e3, args},
+      {ph: 'E', name: 'TaskB', pid, tid, ts: baseTs + 115e3, args},
+    ],
+    [
+      // TaskA overlaps with TaskB, B first
+      {ph: 'B', name: 'TaskA', pid, tid, ts: baseTs, args},
+      {ph: 'X', name: 'TaskB', pid, tid, ts: baseTs + 5e3, dur: 100e3, args},
+      {ph: 'E', name: 'TaskA', pid, tid, ts: baseTs + 90e3, args},
+    ],
+    [
+      // TaskA is missing a B event
+      {ph: 'E', name: 'TaskA', pid, tid, ts: baseTs, args},
+      {ph: 'B', name: 'TaskB', pid, tid, ts: baseTs + 5e3, args},
+      {ph: 'E', name: 'TaskB', pid, tid, ts: baseTs + 115e3, args},
+    ],
+    [
+      // TaskB is missing a B event after an X
+      {ph: 'X', name: 'TaskA', pid, tid, ts: baseTs, dur: 100e3, args},
+      {ph: 'E', name: 'TaskB', pid, tid, ts: baseTs + 10e3, args},
+    ],
+  ];
+
+  for (const invalidEvents of invalidEventSets) {
+    it('should throw on invalid task input', async () => {
+      const traceEvents = [
+        ...boilerplateTrace,
+        ...invalidEvents,
+      ];
+
+      traceEvents.forEach(evt => Object.assign(evt, {cat: 'devtools.timeline'}));
+
+      const context = {computedCache: new Map()};
+      const promise = MainThreadTasks.request({traceEvents}, context);
+      await expect(promise).rejects.toBeTruthy();
+    });
+  }
 });