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Unit testing in Java vs. Smalltalk

When you write unit tests, the minimal requirement before being able to try them out is that they compile. In Smalltalk, this means things like syntactic well-formedness, and perhaps the presence of global variables (i.e. classes) that you reference in the test method body.

It’s very quick and comfortable in Smalltalk to develop supported by unit testing: to write tests you know will fail, and refine away the failures until your test suite passes.

In Java, it’s much less comfortable, because besides the basic requirement of syntactic well-formedness, all the methods, classes, interfaces, and packages that your code relies on, directly or indirectly, must be present in the system before you can even try a run of the test suite! This makes for a less incremental style of development.

It would be very interesting to see a unit-testing framework for Java that simply treated a non-compiling test as a normal test failure, rather than a complete show-stopper, and which let you continue with the other tests in the suite. At the end of a run, it would include the non-compiling tests in the final reports just the same way as any other unexpectedly-failing test is reported.

4 comments February 22nd, 2008 tonyg

Using AMQP to do cron-like scheduling

Barry Pederson’s excellent py-amqplib Python AMQP client comes with a very cute little demo, demonstrating how easy it is to do sophisticated cron-like things with AMQP and RabbitMQ.

As Barry writes in the example, the trick is to “[fire] off simple messages at one-minute intervals to a topic exchange named ‘clock’, with the topic of the message being the local time as ‘year.month.date.dow.hour.minute‘, for example: ‘2007.11.26.1.12.33′, where the dow (day of week) is 0 for Sunday, 1 for Monday, and so on (similar to Unix crontab). A consumer could then bind a queue to the routing key ‘#.0′ for example to get a message at the beginning of each hour.”

Lovely!

1 comment February 8th, 2008 tonyg

How to run RabbitMQ’s experimental STOMP adapter

The code for the experimental STOMP adapter for RabbitMQ is distributed separately from the main server, at the moment. This post walks through the steps needed to try the adapter out, running it against a recent snapshot release of RabbitMQ. The perl Net::Stomp STOMP client is used to demonstrate the adapter in action, subscribing to a queue and sending a couple of messages to it.

Continue Reading 6 comments February 2nd, 2008 tonyg