add failsafe for when app crashes

Signed-off-by: Hanno J. Gödecke <[email protected]>

e2e/server/index.js

@@ -38,6 +38,21 @@ const getPostJSONRequestData = async (req, res) => {
     }
 };
 
+const createListenerState = () => {
+    const listeners = [];
+    const addListener = (listener) => {
+        listeners.push(listener);
+        return () => {
+            const index = listeners.indexOf(listener);
+            if (index !== -1) {
+                listeners.splice(index, 1);
+            }
+        };
+    };
+
+    return [listeners, addListener];
+};
+
 /**
  * The test result object that a client might submit to the server.
  * @typedef TestResult
@@ -63,31 +78,9 @@ const getPostJSONRequestData = async (req, res) => {
  *  It returns an instance to which you can add listeners for the test results, and test done events.
  */
 const createServerInstance = () => {
-    const testResultListeners = [];
-    const testDoneListeners = [];
-
-    /**
-     * Add a callback that will be called when receiving test results.
-     * @param {listener} listener
-     */
-    const addTestResultListener = (listener) => {
-        testResultListeners.push(listener);
-    };
-
-    /**
-     * Will be called when a test signals that it's done.
-     * @param {Function} listener
-     * @returns {Function} A function to remove the listener.
-     */
-    const addTestDoneListener = (listener) => {
-        testDoneListeners.push(listener);
-        return () => {
-            const index = testDoneListeners.indexOf(listener);
-            if (index !== -1) {
-                testDoneListeners.splice(index, 1);
-            }
-        };
-    };
+    const [testStartedListeners, addTestStartedListener] = createListenerState();
+    const [testResultListeners, addTestResultListener] = createListenerState();
+    const [testDoneListeners, addTestDoneListener] = createListenerState();
 
     let activeTestConfig;
 
@@ -102,6 +95,7 @@ const createServerInstance = () => {
         res.statusCode = 200;
         switch (req.url) {
             case Routes.testConfig: {
+                testStartedListeners.forEach(listener => listener(activeTestConfig));
                 if (activeTestConfig == null) {
                     throw new Error('No test config set');
                 }
@@ -137,6 +131,7 @@ const createServerInstance = () => {
 
     return {
         setTestConfig,
+        addTestStartedListener,
         addTestResultListener,
         addTestDoneListener,
         start: () => new Promise(resolve => server.listen(PORT, resolve)),

e2e/testRunner.js

@@ -28,6 +28,7 @@ const math = require('./measure/math');
 const writeTestStats = require('./measure/writeTestStats');
 const withFailTimeout = require('./utils/withFailTimeout');
 const startRecordingVideo = require('./utils/startRecordingVideo');
+const isAppRunning = require('./utils/isAppRunning');
 
 const args = process.argv.slice(2);
 
@@ -104,7 +105,40 @@ const runTestsOnBranch = async (branch, baselineOrCompare) => {
 
             const stopVideoRecording = startRecordingVideo();
 
+            // create a promise that will resolve once the app fetched
+            // the test config, which signals us that the app really started.
+            // Especially on weak systems it can happen that the app crashes during startup.
+            const waitForAppStarted = new Promise((resolve, reject) => {
+                // check every X seconds if the app is still app
+                // it can happen that the app crashes during startup, e.g.
+                // on CI. If this happens we want to try restarting the app.
+                let retries = 0;
+                const intervalId = setInterval(async () => {
+                    try {
+                        await isAppRunning();
+                    } catch (e) {
+                        // !!! the app doesn't seem to be active anymore, try to start it again
+                        if (retries > 10) {
+                            stopVideoRecording(true);
+                            clearInterval(intervalId);
+                            reject(new Error('App crashed during startup'));
+                        }
+                        retries++;
+
+                        Logger.log(`App crashed during startup, restarting app (attempt ${retries}/10)`);
+                        await launchApp('android');
+                    }
+                }, 8000);
+
+                server.addTestStartedListener(() => {
+                    Logger.log(`Test '${config.name}' started!`);
+                    clearInterval(intervalId);
+                    resolve();
+                });
+            });
+
             await restartApp();
+            await waitForAppStarted;
 
             // wait for a test to finish by waiting on its done call to the http server
             try {

e2e/utils/execAsync.js

@@ -24,7 +24,7 @@ module.exports = (command) => {
                 }
             } else {
                 Logger.log(stdout);
-                resolve();
+                resolve(stdout);
             }
         });
     });

e2e/utils/isAppRunning.js

@@ -0,0 +1,8 @@
+const {APP_PACKAGE} = require('../config');
+const execAsync = require('./execAsync');
+
+module.exports = function () {
+    // adb shell pidof
+    const cmd = `adb shell pidof ${APP_PACKAGE}`;
+    return execAsync(cmd);
+};