@Test
public void failsWhenNoImplementationClassSpecifiedInPropertiesFile() throws MalformedURLException {
Properties properties = new Properties();
final TestFile propertiesFile = testDir.file("prop");
GUtil.saveProperties(properties, propertiesFile);
final URL url = propertiesFile.toURI().toURL();
context.checking(new Expectations() {{
allowing(classLoader).getResource("META-INF/gradle-plugins/noImpl.properties");
will(returnValue(url));
}});