Fix for #27

Author: vladimanaev

src/main/java/com/taboola/backstage/internal/SynchronousCallAdapterFactory.java

@@ -67,7 +67,7 @@ public Object adapt(Call<Object> call) {
                             throw new BackstageAPIUnauthorizedException();
 
                         } else if(responseCode >= BAD_REQUEST_HTTP_STATUS_CODE && responseCode < INTERNAL_SERVER_ERROR_HTTP_STATUS_CODE) {
-                            throw new BackstageAPIRequestException(responseCode, parseError(response));
+                            throw new BackstageAPIRequestException(responseCode, normalizeError(parseError(response)));
                         }
 
                         throw new BackstageAPIConnectivityException(responseCode);
@@ -92,4 +92,13 @@ private APIError parseError(Response errorResponse) {
             return new APIError(errorResponse.message(), errorResponse.code());
         }
     }
+
+    APIError normalizeError(APIError error) {
+        String message = error.getMessage();
+        if(message != null) {
+            error.setMessage(message.replaceAll("%", "%%"));
+        }
+
+        return error;
+    }
 }

src/test/java/com/taboola/backstage/internal/SynchronousCallAdapterFactoryTest.java

@@ -1,12 +1,19 @@
 package com.taboola.backstage.internal;
 
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.taboola.backstage.exceptions.BackstageAPIRequestException;
+import com.taboola.backstage.model.APIError;
 import com.taboola.backstage.model.media.campaigns.Campaign;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.junit.Assert;
 import org.junit.Before;
 import org.junit.Test;
 import retrofit2.Call;
 import retrofit2.CallAdapter;
+import static org.junit.Assert.assertEquals;
+
 import com.taboola.backstage.BackstageTestBase;
 
 /**
@@ -17,6 +24,7 @@
  */
 public class SynchronousCallAdapterFactoryTest extends BackstageTestBase {
 
+    private static final Logger logger = LogManager.getLogger(SynchronousCallAdapterFactoryTest.class);
     private SynchronousCallAdapterFactory testInstance;
 
     @Before
@@ -41,5 +49,14 @@ public void testSynchronousAdapterForCallType() {
         Assert.assertNull("Invalid adapter, expecting no adapter", actualAdapter);
     }
 
+    @Test
+    public void testParseError_whenErrorMsgContainsPercentSign_expectingValidFormatForStringFormat() {
+        APIError apiError = new APIError("Cpc boost value must be between -99% and 100%", 400);
+        apiError = testInstance.normalizeError(apiError);
+        BackstageAPIRequestException ex = new BackstageAPIRequestException(400, apiError);
+        logger.info(ex);
+        assertEquals("Failed to perform API call with response code [400]. Response payload status [400], message [Cpc boost value must be between -99% and 100%], offending field [null]", ex.getMessage());
+    }
+
     //TODO add more tests - retrofit2#Response.class is final therefore mockito is not working on it
 }