Add tests.

Author: qdpham13

firebase-config/src/main/java/com/google/firebase/remoteconfig/internal/ConfigRealtimeHttpClient.java

@@ -236,7 +236,8 @@ private URL getUrl() {
     return realtimeURL;
   }
 
-  private HttpURLConnection createRealtimeConnection() throws IOException {
+  @SuppressLint("VisibleForTests")
+  public HttpURLConnection createRealtimeConnection() throws IOException {
     URL realtimeUrl = getUrl();
     HttpURLConnection httpURLConnection = (HttpURLConnection) realtimeUrl.openConnection();
     setCommonRequestHeaders(httpURLConnection);
@@ -246,7 +247,8 @@ private HttpURLConnection createRealtimeConnection() throws IOException {
   }
 
   // Try to reopen HTTP connection after a random amount of time
-  private synchronized void retryHTTPConnection() {
+  @SuppressLint("VisibleForTests")
+  public synchronized void retryHTTPConnection() {
     if (canMakeHttpStreamConnection() && httpRetriesRemaining > 0) {
       if (httpRetriesRemaining < ORIGINAL_RETRIES) {
         httpRetrySeconds *= getRetryMultiplier();
@@ -314,7 +316,7 @@ private boolean isStatusCodeRetryable(int statusCode) {
    * chunk-encoded HTTP body. When the connection closes, it attempts to reestablish the stream.
    */
   @SuppressLint("VisibleForTests")
-  synchronized void beginRealtimeHttpStream() {
+  public synchronized void beginRealtimeHttpStream() {
     if (!canMakeHttpStreamConnection()) {
       return;
     }

firebase-config/src/test/java/com/google/firebase/remoteconfig/FirebaseRemoteConfigTest.java

@@ -65,6 +65,7 @@
 import com.google.firebase.remoteconfig.internal.ConfigGetParameterHandler;
 import com.google.firebase.remoteconfig.internal.ConfigMetadataClient;
 import com.google.firebase.remoteconfig.internal.ConfigRealtimeHandler;
+import com.google.firebase.remoteconfig.internal.ConfigRealtimeHttpClient;
 import com.google.firebase.remoteconfig.internal.Personalization;
 import java.io.ByteArrayInputStream;
 import java.io.IOException;
@@ -140,6 +141,7 @@ public final class FirebaseRemoteConfigTest {
   @Mock private ConfigMetadataClient metadataClient;
 
   @Mock private ConfigRealtimeHandler mockConfigRealtimeHandler;
+  @Mock private ConfigRealtimeHttpClient mockConfigRealtimeHttpClient;
   @Mock private ConfigUpdateListenerRegistration mockRealtimeRegistration;
   @Mock private HttpURLConnection mockHttpURLConnection;
   @Mock private ConfigUpdateListener mockListener;
@@ -1203,6 +1205,14 @@ public void realtime_stream_autofetch_failure() {
     verify(mockListener).onError(any(FirebaseRemoteConfigRealtimeUpdateFetchException.class));
   }
 
+  @Test
+  public void realtime_checkStatusCode_beforeRetryStream() throws Exception {
+    when(mockConfigRealtimeHttpClient.createRealtimeConnection()).thenReturn(mockHttpURLConnection);
+    when(mockHttpURLConnection.getResponseCode()).thenReturn(502);
+    mockConfigRealtimeHttpClient.beginRealtimeHttpStream();
+    verify(mockConfigRealtimeHttpClient, never()).retryHTTPConnection();
+  }
+
   private static void loadCacheWithConfig(
       ConfigCacheClient cacheClient, ConfigContainer container) {
     when(cacheClient.getBlocking()).thenReturn(container);