UrlStreamsTest.java

package games.strategy.util;

import static org.hamcrest.MatcherAssert.assertThat;
import static org.hamcrest.Matchers.sameInstance;
import static org.hamcrest.core.Is.is;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.when;

import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;
import java.util.Optional;

import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.Mock;
import org.mockito.junit.MockitoJUnitRunner;

@RunWith(MockitoJUnitRunner.class)
public class UrlStreamsTest {

  private UrlStreams testObj;

  private URL fakeUrl;

  @Mock
  private URLConnection mockUrlConnection;
  @Mock
  private InputStream mockInputStream;


  @Before
  public void setup() throws Exception {
    // set up the test object with a function that will return a mocked url connection
    testObj = new UrlStreams(url -> mockUrlConnection);
    fakeUrl = new URL("http://well-formed-url.com");
  }

  /**
   * Check that we turned off caching on a mocked UrlConnection.
   */
  @Test
  public void cacheIsOff() throws Exception {
    when(mockUrlConnection.getInputStream()).thenReturn(mockInputStream);

    final Optional<InputStream> connection = testObj.newStream(fakeUrl);

    assertThat("expecting the same mocked http connection object back",
        connection.get(), sameInstance(mockInputStream));
    verify(mockUrlConnection).setUseCaches(false);
    verify(mockUrlConnection).setDefaultUseCaches(false);
  }


  @Test
  public void testErrorSuppressionWhenThereIsNoError() throws Exception {
    when(mockUrlConnection.getInputStream()).thenReturn(mockInputStream);

    final Optional<InputStream> stream = testObj.newStream(fakeUrl);

    assertThat("No issues connecting, we should have an inpuct stream back.",
        stream.isPresent(), is(true));
  }

  @Test
  public void testErrorSuppression() throws Exception {
    when(mockUrlConnection.getInputStream()).thenThrow(new IOException("simulating an IOException being thrown"));

    final Optional<InputStream> stream = testObj.newStream(fakeUrl);

    assertThat("No exceptions expected, but a failure to connect should return an empty object.",
        stream.isPresent(), is(false));
  }

}