releaseDescriptor.setScmSourceUrl( "scm-url" );
File checkoutDirectory = getTestFile( "target/checkout-directory" );
releaseDescriptor.setCheckoutDirectory( checkoutDirectory.getAbsolutePath() );
ScmProvider scmProviderMock = mock( ScmProvider.class );
when( scmProviderMock.checkOut( any( ScmRepository.class ), any( ScmFileSet.class ), any ( ScmTag.class ) ) ).thenThrow( new ScmException( "..." ) );
ScmManagerStub stub = (ScmManagerStub) lookup( ScmManager.ROLE );
stub.setScmProvider( scmProviderMock );
// execute