fix: throws AlreadyConfiguredException when configured == true (#1274)

Author: haverchuck

core/src/main/java/com/amplifyframework/core/Amplify.java

@@ -37,7 +37,6 @@
 import com.amplifyframework.util.UserAgent;
 
 import java.util.LinkedHashMap;
-import java.util.Locale;
 import java.util.Map;
 import java.util.Objects;
 import java.util.concurrent.ExecutorService;
@@ -137,7 +136,7 @@ public static void configure(@NonNull final AmplifyConfiguration configuration,
 
         synchronized (CONFIGURATION_LOCK) {
             if (CONFIGURATION_LOCK.get()) {
-                throw new AlreadyConfiguredException();
+                throw new AlreadyConfiguredException("Remove the duplicate call to `Amplify.configure()`.");
             }
 
             // Configure User-Agent utility
@@ -192,11 +191,7 @@ private static <P extends Plugin<?>> void updatePluginRegistry(
 
         synchronized (CONFIGURATION_LOCK) {
             if (CONFIGURATION_LOCK.get()) {
-                final String updateString = registryUpdateType.name().toLowerCase(Locale.US);
-                throw new AmplifyException(
-                    "The client tried to " + updateString + " a plugin after calling configure().",
-                        "Plugins may not be added or removed after configure(...) is called."
-                );
+                throw new AlreadyConfiguredException("Do not add plugins after calling `Amplify.configure()`.");
             }
 
             if (Empty.check(plugin.getPluginKey())) {
@@ -246,8 +241,8 @@ public static final class AlreadyConfiguredException extends AmplifyException {
         /**
          * Constructs an AlreadyConfiguredException, indicating that Amplify has already been configured.
          */
-        private AlreadyConfiguredException() {
-            super("Amplify has already been configured.", "Remove the duplicate call to `Amplify.configure()`");
+        private AlreadyConfiguredException(@NonNull String recoverySuggestion) {
+            super("Amplify has already been configured.", recoverySuggestion);
         }
     }
 }

core/src/test/java/com/amplifyframework/core/AmplifyTest.java

@@ -19,6 +19,7 @@
 import android.os.Build;
 
 import com.amplifyframework.AmplifyException;
+import com.amplifyframework.core.plugin.Plugin;
 
 import org.json.JSONObject;
 import org.junit.FixMethodOrder;
@@ -90,8 +91,32 @@ public void reconfigurationAttemptRaisesException() throws AmplifyException {
             actuallyThrown.getMessage()
         );
         assertEquals(
-            "Remove the duplicate call to `Amplify.configure()`",
+            "Remove the duplicate call to `Amplify.configure()`.",
             actuallyThrown.getRecoverySuggestion()
         );
     }
+
+    /**
+     * It is an error to call {@link Amplify#addPlugin(Plugin)}} after configuration.
+     * @throws Amplify.AlreadyConfiguredException
+     *  NOTE: The name of this method must result in it running last, according to {@link FixMethodOrder}
+     */
+    @Test
+    public void secondaryAddPluginAfterConfigurationRaisesException() throws Amplify.AlreadyConfiguredException {
+        final SimpleLoggingPlugin loggingPlugin = SimpleLoggingPlugin.instance();
+        Amplify.AlreadyConfiguredException actuallyThrown =
+            assertThrows(
+                Amplify.AlreadyConfiguredException.class,
+                () -> Amplify.addPlugin(loggingPlugin)
+            );
+
+        assertEquals(
+                "Amplify has already been configured.",
+                actuallyThrown.getMessage()
+        );
+        assertEquals(
+                "Do not add plugins after calling `Amplify.configure()`.",
+                actuallyThrown.getRecoverySuggestion()
+        );
+    }
 }