Announcing spect, a helping library for Test::Unit
Clinton R. Dreisbach, Former Viget
We've tried out a lot of test frameworks for Ruby here at the Lab. I have been a big fan of test/spec in the past, and like shoulda's nested contexts. test/spec's wrapped assertions - like
user.should.not.be.nil instead of
assert_not_nil user - are a particular feature I dig.
I wanted to use these with shoulda, and started to extend shoulda to have its own set of wrapped assertions, but when I looked in the test/spec code, I saw this beauty:
module Test::Spec class Should ... def add_assertion $TEST_SPEC_TESTCASE && $TEST_SPEC_TESTCASE.__send__(:add_assertion) end ... end class TestCase ... module InstanceMethods def setup # :nodoc: $TEST_SPEC_TESTCASE = self super call_methods_including_parents(:setups) end ... end ... end end
I don't want to put down a piece of code I've used a lot and enjoyed, and I think this is a practical way for test/spec to handle increasing the assertion count for its wrapped assertions, since they all start with a method on
Object. I, however, couldn't bring myself to use a global variable to handle this task. I thought for a while, and after being inspired by JDave, I decided to start with a method on
I released my test library today as a Ruby gem called spect. It's very simple to use. Once you require spect, you can use the method
Test::Unit::TestCase or any derived classes, like a shoulda
should block or a test/spec
expect sets up expectations like the following:
expect(user).responds_to admin? expect(user).is.an.admin expect(user.name).to.not.match /mr_jenkins/ expect(user).to.be.equal User.find(:first) expect(user).is.not.not.not.not user expect(ZeroDivisionError).raised_by do user.id / 0 end
Most of the Test::Unit assertions are wrapped, with the following mappings:
In addition, all predicates on an object can be tested for truth by calling them per normal (
admin?) or by dropping the question mark (
There are several methods used solely for grammatical purposes.
a are no-ops and just return
be are no-ops unless they are passed an argument, in which case they assert equality between the original object and this argument.
not reverses assertions, but also can be passed an argument to assert inequality.
I am sure there are a lot of improvements to make. I thought of one writing this blog post (
equal_to should be an alias for
equal.) I invite you to check out the code at our GitHub repository and submit patches.