Is there a simple way to match a field using Hamcrest?

Question

I want to test whether a specific field of an object matches a value I specify. In this case, it\'s the bucket name inside an S3Bucket object. As far as I can tell, I need t

Answer 1

There is a neat way of doing this with LambdaJ:

mockery.checking(new Expectations() {{
  one(query.s3).getObject(
    with(having(on(S3Bucket.class).getName(), is("bucket")))
  )
}});

Answer 2

Sounds like you need to use Matchers.hasProperty, e.g.

mockery.checking(new Expectations() {{
  one(query.s3).getObject(
    with(hasProperty("name", "bucket")),
    with(equal("key")));
    ...
}});

Or something similar.

Answer 3

Alternatively, for a more typesafe version, there's the FeatureMatcher. In this case, something like:

private Matcher<S3Bucket> bucketName(final String expected) {
  return new FeatureMatcher<S3Bucket, String>(equalTo(expected), 
                                              "bucket called", "name") {
     String featureValueOf(S3Bucket actual) {
       return actual.getName();
     }
  };
}

giving:

mockery.checking(new Expectations() {{
  one(query.s3).getObject(with(bucketName("bucket")), with(equalTo("key")));
    ...
}});

The purpose of the two string arguments is to make the mismatch report read well.