Fix crash in error handling of IOExceptions without messages

Author: rubengees

gradle/versions.gradle

@@ -26,6 +26,7 @@ ext {
 
     junitVersion = '4.12'
     assertjVersion = '3.11.0'
+    mockitoVersion = '2.22.0'
     privateConstructorVersion = '1.2.0'
 
     deps = [
@@ -42,6 +43,7 @@ ext {
 
             junit             : "junit:junit:$junitVersion",
             assertj           : "org.assertj:assertj-core:$assertjVersion",
+            mockito           : "org.mockito:mockito-android:$mockitoVersion",
             okhttpTls         : "com.squareup.okhttp3:okhttp-tls:$okHttpVersion",
             mockwebserver     : "com.squareup.okhttp3:mockwebserver:$okHttpVersion",
             privateConstructor: "com.pushtorefresh.java-private-constructor-checker:checker:$privateConstructorVersion"

library/build.gradle

@@ -44,6 +44,7 @@ dependencies {
 
     testImplementation deps.junit
     testImplementation deps.assertj
+    testImplementation deps.mockito
     testImplementation deps.okhttpTls
     testImplementation deps.mockwebserver
     testImplementation deps.privateConstructor

library/src/main/java/me/proxer/library/api/ProxerCall.java

@@ -149,7 +149,7 @@ private ProxerException processNonProxerError(final Exception error) {
         if (error instanceof SocketTimeoutException) {
             return new ProxerException(ProxerException.ErrorType.TIMEOUT, error);
         } else if (error instanceof IOException) {
-            if (error.getMessage().equals("Canceled")) {
+            if (error.getMessage() != null && error.getMessage().equals("Canceled")) {
                 return new ProxerException(ProxerException.ErrorType.CANCELLED, error);
             } else {
                 return new ProxerException(ProxerException.ErrorType.IO, error);

library/src/test/java/me/proxer/library/api/ProxerCallTest.java

@@ -7,13 +7,16 @@
 import okhttp3.mockwebserver.MockResponse;
 import okhttp3.mockwebserver.SocketPolicy;
 import org.junit.Test;
+import retrofit2.Call;
 
 import java.io.IOException;
 import java.util.List;
 import java.util.concurrent.CountDownLatch;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
 
 /**
  * @author Ruben Gees
@@ -172,4 +175,18 @@ public void testClone() throws ProxerException, IOException {
     public void testRequest() {
         assertThat(api.notifications().news().build().request()).isNotNull();
     }
+
+    @SuppressWarnings("unchecked")
+    @Test
+    public void testRequestThrowingErrorWithoutMessage() throws IOException {
+        final Call<ProxerResponse<NewsArticle>> mockedCall = mock(Call.class);
+        final ProxerCall<NewsArticle> call = new ProxerCall<>(mockedCall);
+
+        when(mockedCall.execute()).thenThrow(new IOException());
+
+        assertThatExceptionOfType(ProxerException.class)
+                .isThrownBy(call::execute)
+                .withCauseExactlyInstanceOf(IOException.class)
+                .matches(it -> it.getErrorType() == ErrorType.IO);
+    }
 }