Chain cause in ComputeException.translateAndThrow, add tests (#948)

Chain cause in ComputeException.translateAndThrow, add tests and make ComputeException constructors package scoped.

Author: mziccard

gcloud-java-compute/src/main/java/com/google/gcloud/compute/ComputeException.java

@@ -32,8 +32,12 @@ public class ComputeException extends BaseServiceException {
   private static final Set<Error> RETRYABLE_ERRORS = ImmutableSet.of(new Error(500, null));
   private static final long serialVersionUID = -8039359778707845810L;
 
-  public ComputeException(int code, String message) {
-    super(code, message, null, true);
+  ComputeException(int code, String message) {
+    super(code, message, null, true, null);
+  }
+
+  ComputeException(int code, String message, Throwable cause) {
+    super(code, message, null, true, cause);
   }
 
   public ComputeException(IOException exception) {
@@ -54,6 +58,6 @@ protected Set<Error> retryableErrors() {
    */
   static BaseServiceException translateAndThrow(RetryHelperException ex) {
     BaseServiceException.translateAndPropagateIfPossible(ex);
-    throw new ComputeException(UNKNOWN_CODE, ex.getMessage());
+    throw new ComputeException(UNKNOWN_CODE, ex.getMessage(), ex.getCause());
   }
 }

gcloud-java-compute/src/test/java/com/google/gcloud/compute/ComputeExceptionTest.java

@@ -0,0 +1,105 @@
+/*
+ * Copyright 2016 Google Inc. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.gcloud.compute;
+
+import static org.easymock.EasyMock.createMock;
+import static org.easymock.EasyMock.expect;
+import static org.easymock.EasyMock.replay;
+import static org.easymock.EasyMock.verify;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertSame;
+import static org.junit.Assert.assertTrue;
+
+import com.google.gcloud.BaseServiceException;
+import com.google.gcloud.RetryHelper.RetryHelperException;
+
+import org.junit.Test;
+
+import java.io.IOException;
+import java.net.SocketTimeoutException;
+
+public class ComputeExceptionTest {
+
+  @Test
+  public void testResourceManagerException() {
+    ComputeException exception = new ComputeException(500, "message");
+    assertEquals(500, exception.code());
+    assertEquals("message", exception.getMessage());
+    assertNull(exception.reason());
+    assertTrue(exception.retryable());
+    assertTrue(exception.idempotent());
+
+    exception = new ComputeException(403, "message");
+    assertEquals(403, exception.code());
+    assertEquals("message", exception.getMessage());
+    assertNull(exception.reason());
+    assertFalse(exception.retryable());
+    assertTrue(exception.idempotent());
+
+    IOException cause = new SocketTimeoutException();
+    exception = new ComputeException(cause);
+    assertNull(exception.reason());
+    assertNull(exception.getMessage());
+    assertTrue(exception.retryable());
+    assertTrue(exception.idempotent());
+    assertSame(cause, exception.getCause());
+
+    exception = new ComputeException(403, "message", cause);
+    assertEquals(403, exception.code());
+    assertEquals("message", exception.getMessage());
+    assertNull(exception.reason());
+    assertFalse(exception.retryable());
+    assertTrue(exception.idempotent());
+    assertSame(cause, exception.getCause());
+  }
+
+  @Test
+  public void testTranslateAndThrow() throws Exception {
+    Exception cause = new ComputeException(500, "message");
+    RetryHelperException exceptionMock = createMock(RetryHelperException.class);
+    expect(exceptionMock.getCause()).andReturn(cause).times(2);
+    replay(exceptionMock);
+    try {
+      ComputeException.translateAndThrow(exceptionMock);
+    } catch (BaseServiceException ex) {
+      assertEquals(500, ex.code());
+      assertEquals("message", ex.getMessage());
+      assertTrue(ex.retryable());
+      assertTrue(ex.idempotent());
+    } finally {
+      verify(exceptionMock);
+    }
+    cause = new IllegalArgumentException("message");
+    exceptionMock = createMock(RetryHelperException.class);
+    expect(exceptionMock.getMessage()).andReturn("message").times(1);
+    expect(exceptionMock.getCause()).andReturn(cause).times(2);
+    replay(exceptionMock);
+    try {
+      ComputeException.translateAndThrow(exceptionMock);
+    } catch (BaseServiceException ex) {
+      assertEquals(ComputeException.UNKNOWN_CODE, ex.code());
+      assertEquals("message", ex.getMessage());
+      assertFalse(ex.retryable());
+      assertTrue(ex.idempotent());
+      assertSame(cause, ex.getCause());
+    } finally {
+      verify(exceptionMock);
+    }
+  }
+}