Fix random errors of e2e tests. Don't run some code if unnecessary.

MyTracksTest/src/com/google/android/apps/mytracks/endtoendtest/EndToEndTestUtils.java

@@ -508,8 +508,10 @@ public class EndToEndTestUtils {
    * is shown.
    */
   public static void deleteAllTracks() {
-    findMenuItem(activityMytracks.getString(R.string.menu_delete_all), true);
-    getButtonOnScreen(activityMytracks.getString(R.string.generic_ok), true, true);
+    if (!isTrackListEmpty(false)) {
+      findMenuItem(activityMytracks.getString(R.string.menu_delete_all), true);
+      getButtonOnScreen(activityMytracks.getString(R.string.generic_ok), true, true);
+    }
   }
   
   /**
@@ -831,6 +833,8 @@ public class EndToEndTestUtils {
     SOLO.waitForText(activityMyTracks.getString(R.string.settings_reset));
     SOLO.clickOnText(activityMyTracks.getString(R.string.settings_reset));
     getButtonOnScreen(activityMytracks.getString(R.string.generic_ok), true, true);
+    Assert.assertTrue(SOLO.waitForText(activityMyTracks.getString(R.string.settings_reset_done)));
+
     instrumentation.waitForIdleSync();
     if (!keepInSettingList) {
       SOLO.goBack();

MyTracksTest/src/com/google/android/apps/mytracks/endtoendtest/others/SensorTest.java

@@ -49,6 +49,9 @@ public class SensorTest extends ActivityInstrumentationTestCase2<TrackListActivi
   @Override
   protected void setUp() throws Exception {
     super.setUp();
+    if (!testSensor) {
+      return;
+    }
     instrumentation = getInstrumentation();
     activityMyTracks = getActivity();
     EndToEndTestUtils.setupForAllTest(instrumentation, activityMyTracks);

MyTracksTest/src/com/google/android/apps/mytracks/endtoendtest/others/StressTest.java

@@ -49,6 +49,9 @@ public class StressTest extends ActivityInstrumentationTestCase2<TrackListActivi
   @Override
   protected void setUp() throws Exception {
     super.setUp();
+    if (!testStress) {
+      return;
+    }
     instrumentation = getInstrumentation();
     activityMyTracks = getActivity();
     EndToEndTestUtils.setupForDebug(instrumentation, activityMyTracks);