@Test(expected = MojoFailureException.class)
public void testAddTargets_throws() throws Exception {

    WebsterMojo mojo = newMojo();
    mojo.baseDir = new File(".");
    mojo.websterTargets = obj().get();
    mojo.addTargets(new WebsterPlan.Builder(), (baseDir, targets) -> {
        throw new IOException("failed yo");
    });
}