/*
* Copyright 2011-2017 Amazon.com, Inc. or its affiliates. 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.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file 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.amazonaws.regions;
import com.amazonaws.AmazonClientException;
import org.junit.Test;
import static org.junit.Assert.assertEquals;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.never;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.when;
public class AwsRegionProviderChainTest {
@Test
public void firstProviderInChainGivesRegionInformation_DoesNotConsultOtherProviders() {
AwsRegionProvider providerOne = mock(AwsRegionProvider.class);
AwsRegionProvider providerTwo = mock(AwsRegionProvider.class);
AwsRegionProvider providerThree = mock(AwsRegionProvider.class);
AwsRegionProviderChain chain = new AwsRegionProviderChain(providerOne, providerTwo,
providerThree);
final String expectedRegion = "some-region-string";
when(providerOne.getRegion()).thenReturn(expectedRegion);
assertEquals(expectedRegion, chain.getRegion());
verify(providerTwo, never()).getRegion();
verify(providerThree, never()).getRegion();
}
@Test
public void lastProviderInChainGivesRegionInformation() {
final String expectedRegion = "some-region-string";
AwsRegionProviderChain chain = new AwsRegionProviderChain(new NeverAwsRegionProvider(),
new NeverAwsRegionProvider(),
new StaticAwsRegionProvider(
expectedRegion));
assertEquals(expectedRegion, chain.getRegion());
}
@Test
public void providerThrowsException_ContinuesToNextInChain() {
final String expectedRegion = "some-region-string";
AwsRegionProviderChain chain = new AwsRegionProviderChain(new NeverAwsRegionProvider(),
new FaultyAwsRegionProvider(),
new StaticAwsRegionProvider(
expectedRegion));
assertEquals(expectedRegion, chain.getRegion());
}
/**
* Only Exceptions should be caught and continued, Errors should propagate to caller and short
* circuit the chain.
*/
@Test(expected = Error.class)
public void providerThrowsError_DoesNotContinueChain() {
final String expectedRegion = "some-region-string";
AwsRegionProviderChain chain = new AwsRegionProviderChain(new NeverAwsRegionProvider(),
new FatalAwsRegionProvider(),
new StaticAwsRegionProvider(
expectedRegion));
assertEquals(expectedRegion, chain.getRegion());
}
@Test(expected = AmazonClientException.class)
public void noProviderGivesRegion_ThrowsAmazonClientException() {
AwsRegionProviderChain chain = new AwsRegionProviderChain(new NeverAwsRegionProvider(),
new NeverAwsRegionProvider(),
new NeverAwsRegionProvider());
chain.getRegion();
}
private static class NeverAwsRegionProvider extends AwsRegionProvider {
@Override
public String getRegion() throws AmazonClientException {
return null;
}
}
private static class StaticAwsRegionProvider extends AwsRegionProvider {
private final String region;
public StaticAwsRegionProvider(String region) {
this.region = region;
}
@Override
public String getRegion() {
return region;
}
}
private static class FaultyAwsRegionProvider extends AwsRegionProvider {
@Override
public String getRegion() throws AmazonClientException {
throw new AmazonClientException("Unable to fetch region info");
}
}
private static class FatalAwsRegionProvider extends AwsRegionProvider {
@Override
public String getRegion() throws AmazonClientException {
throw new Error("Something really bad happened");
}
}
}