STITCH-2263 - Android SDK: Always run R2L synchronization first

README.md

@@ -108,9 +108,14 @@ implementation 'org.mongodb:stitch-server-services-twilio:4.1.3'
 
 1. In Android Studio, go to Tools, Android, AVD manager.
 2. Click Create Virtual Device.
-3. Select a device that should run your app (the default is fine).
+3. Select a device that should run your app (as of Android Studio 3.2, the default device does not work properly for this purpose).
 4. Select and download a recommended system image of your choice (the latest is fine).
-	* x86_64 images are available in the x86 tab.
+    * This device must use a system image built on an architecture supported by the
+```libmongo``` library, e.g. x86_64
+        * x86 images are unsupported
+        * x86_64 images are available in the x86 tab.
+    * The current minimum Android API version: 21
+    * Please consult the the [MongoDB Mobile Documentation](https://docs.mongodb.com/stitch/mongodb/mobile/getting-started/) for more information about minimum device requirements.
 5. Name your device and hit finish.
 
 #### Using the SDK

contrib/README.md

@@ -37,4 +37,15 @@ The general publishing flow can be followed using `minor` as the bump type in `b
 
 ### Major Versions
 
-The general publishing flow can be followed using `major` as the bump type in `bump_version`. In addition to this, the release on GitHub should be edited for a more readable format of key changes and include any migration steps needed to go from the last major version to this one.
+The general publishing flow can be followed using `major` as the bump type in `bump_version`. In addition to this, the release on GitHub should be edited for a more readable format of key changes and include any migration steps needed to go from the last major version to this one.
+
+### Testing (MongoDB Internal Contributors Only)
+
+* Before committing, the ```connectedDebugAndroidTest``` suite of integration tests must succeed.
+* The tests require the following setup:
+    * You must enable clear text traffic in the core Android application locally (**do not commit this change**)
+        * In file *android/core/src/main/AndroidManifest.xml*, change the ```application``` XML tag as follows:
+            ```<application android:usesCleartextTraffic="true">```
+    * You must run at least one ```mongod``` instance with replica sets initiated or a ```mongos``` instance with same locally on port 27000
+    * You must run the Stitch server locally using the Android-specific configuration:
+        ```--configFile ./etc/configs/test_config_sdk_base.json --configFile ./etc/configs/test_config_sdk_android.json```

core/services/mongodb-remote/src/main/java/com/mongodb/stitch/core/services/mongodb/remote/sync/internal/DataSynchronizer.java

@@ -432,22 +432,6 @@ public void close() {
 
   // ---- Core Synchronization Logic -----
 
-  private boolean localToRemoteFirst = false;
-
-  /**
-   * Swaps which sync direction comes first. Note: this should only be used for testing purposes.
-   *
-   * @param localToRemoteFirst whether or not L2R should go first.
-   */
-  public void swapSyncDirection(final boolean localToRemoteFirst) {
-    syncLock.lock();
-    try {
-      this.localToRemoteFirst = localToRemoteFirst;
-    } finally {
-      syncLock.unlock();
-    }
-  }
-
   /**
    * Performs a single synchronization pass in both the local and remote directions; the order
    * of which does not matter. If switching the order produces different results after one pass,
@@ -485,13 +469,8 @@ public boolean doSyncPass() {
         return false;
       }
 
-      if (localToRemoteFirst) {
-        syncLocalToRemote();
-        syncRemoteToLocal();
-      } else {
-        syncRemoteToLocal();
-        syncLocalToRemote();
-      }
+      syncRemoteToLocal();
+      syncLocalToRemote();
 
       logger.info(String.format(
           Locale.US,