Hey everyone, I've just published a blog post about the new TestStream primitive, which lets us write tests for Pipelines that have code that handles out-of-order or delayed data. It includes some examples of all the ways a Beam pipeline can produce output, how the model handles late data, and then goes into detail about the implementation of TestStream.
Check it out! http://beam.incubator.apache.org/blog/2016/10/20/test-stream.html Yours, Thomas
