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Edit File: unit.rb
require 'test/unit/testcase' require 'test/unit/autorunner' module Test # :nodoc: # # = Test::Unit - Ruby Unit Testing Framework # # == Introduction # # Unit testing is making waves all over the place, largely due to the # fact that it is a core practice of XP. While XP is great, unit testing # has been around for a long time and has always been a good idea. One # of the keys to good unit testing, though, is not just writing tests, # but having tests. What's the difference? Well, if you just _write_ a # test and throw it away, you have no guarantee that something won't # change later which breaks your code. If, on the other hand, you _have_ # tests (obviously you have to write them first), and run them as often # as possible, you slowly build up a wall of things that cannot break # without you immediately knowing about it. This is when unit testing # hits its peak usefulness. # # Enter Test::Unit, a framework for unit testing in Ruby, helping you to # design, debug and evaluate your code by making it easy to write and # have tests for it. # # # == Notes # # Test::Unit has grown out of and superceded Lapidary. # # # == Feedback # # I like (and do my best to practice) XP, so I value early releases, # user feedback, and clean, simple, expressive code. There is always # room for improvement in everything I do, and Test::Unit is no # exception. Please, let me know what you think of Test::Unit as it # stands, and what you'd like to see expanded/changed/improved/etc. If # you find a bug, let me know ASAP; one good way to let me know what the # bug is is to submit a new test that catches it :-) Also, I'd love to # hear about any successes you have with Test::Unit, and any # documentation you might add will be greatly appreciated. My contact # info is below. # # # == Contact Information # # A lot of discussion happens about Ruby in general on the ruby-talk # mailing list (http://www.ruby-lang.org/en/ml.html), and you can ask # any questions you might have there. I monitor the list, as do many # other helpful Rubyists, and you're sure to get a quick answer. Of # course, you're also welcome to email me (Nathaniel Talbott) directly # at mailto:testunit@talbott.ws, and I'll do my best to help you out. # # # == Credits # # I'd like to thank... # # Matz, for a great language! # # Masaki Suketa, for his work on RubyUnit, which filled a vital need in # the Ruby world for a very long time. I'm also grateful for his help in # polishing Test::Unit and getting the RubyUnit compatibility layer # right. His graciousness in allowing Test::Unit to supercede RubyUnit # continues to be a challenge to me to be more willing to defer my own # rights. # # Ken McKinlay, for his interest and work on unit testing, and for his # willingness to dialog about it. He was also a great help in pointing # out some of the holes in the RubyUnit compatibility layer. # # Dave Thomas, for the original idea that led to the extremely simple # "require 'test/unit'", plus his code to improve it even more by # allowing the selection of tests from the command-line. Also, without # RDoc, the documentation for Test::Unit would stink a lot more than it # does now. # # Everyone who's helped out with bug reports, feature ideas, # encouragement to continue, etc. It's a real privilege to be a part of # the Ruby community. # # The guys at RoleModel Software, for putting up with me repeating, "But # this would be so much easier in Ruby!" whenever we're coding in Java. # # My Creator, for giving me life, and giving it more abundantly. # # # == License # # Test::Unit is copyright (c) 2000-2003 Nathaniel Talbott. It is free # software, and is distributed under the Ruby license. See the COPYING # file in the standard Ruby distribution for details. # # # == Warranty # # This software is provided "as is" and without any express or # implied warranties, including, without limitation, the implied # warranties of merchantibility and fitness for a particular # purpose. # # # == Author # # Nathaniel Talbott. # Copyright (c) 2000-2003, Nathaniel Talbott # # ---- # # = Usage # # The general idea behind unit testing is that you write a _test_ # _method_ that makes certain _assertions_ about your code, working # against a _test_ _fixture_. A bunch of these _test_ _methods_ are # bundled up into a _test_ _suite_ and can be run any time the # developer wants. The results of a run are gathered in a _test_ # _result_ and displayed to the user through some UI. So, lets break # this down and see how Test::Unit provides each of these necessary # pieces. # # # == Assertions # # These are the heart of the framework. Think of an assertion as a # statement of expected outcome, i.e. "I assert that x should be equal # to y". If, when the assertion is executed, it turns out to be # correct, nothing happens, and life is good. If, on the other hand, # your assertion turns out to be false, an error is propagated with # pertinent information so that you can go back and make your # assertion succeed, and, once again, life is good. For an explanation # of the current assertions, see Test::Unit::Assertions. # # # == Test Method & Test Fixture # # Obviously, these assertions have to be called within a context that # knows about them and can do something meaningful with their # pass/fail value. Also, it's handy to collect a bunch of related # tests, each test represented by a method, into a common test class # that knows how to run them. The tests will be in a separate class # from the code they're testing for a couple of reasons. First of all, # it allows your code to stay uncluttered with test code, making it # easier to maintain. Second, it allows the tests to be stripped out # for deployment, since they're really there for you, the developer, # and your users don't need them. Third, and most importantly, it # allows you to set up a common test fixture for your tests to run # against. # # What's a test fixture? Well, tests do not live in a vacuum; rather, # they're run against the code they are testing. Often, a collection # of tests will run against a common set of data, also called a # fixture. If they're all bundled into the same test class, they can # all share the setting up and tearing down of that data, eliminating # unnecessary duplication and making it much easier to add related # tests. # # Test::Unit::TestCase wraps up a collection of test methods together # and allows you to easily set up and tear down the same test fixture # for each test. This is done by overriding #setup and/or #teardown, # which will be called before and after each test method that is # run. The TestCase also knows how to collect the results of your # assertions into a Test::Unit::TestResult, which can then be reported # back to you... but I'm getting ahead of myself. To write a test, # follow these steps: # # * Make sure Test::Unit is in your library path. # * require 'test/unit' in your test script. # * Create a class that subclasses Test::Unit::TestCase. # * Add a method that begins with "test" to your class. # * Make assertions in your test method. # * Optionally define #setup and/or #teardown to set up and/or tear # down your common test fixture. # * You can now run your test as you would any other Ruby # script... try it and see! # # A really simple test might look like this (#setup and #teardown are # commented out to indicate that they are completely optional): # # require 'test/unit' # # class TC_MyTest < Test::Unit::TestCase # # def setup # # end # # # def teardown # # end # # def test_fail # assert(false, 'Assertion was false.') # end # end # # # == Test Runners # # So, now you have this great test class, but you still need a way to # run it and view any failures that occur during the run. This is # where Test::Unit::UI::Console::TestRunner (and others, such as # Test::Unit::UI::GTK::TestRunner) comes into play. The console test # runner is automatically invoked for you if you require 'test/unit' # and simply run the file. To use another runner, or to manually # invoke a runner, simply call its run class method and pass in an # object that responds to the suite message with a # Test::Unit::TestSuite. This can be as simple as passing in your # TestCase class (which has a class suite method). It might look # something like this: # # require 'test/unit/ui/console/testrunner' # Test::Unit::UI::Console::TestRunner.run(TC_MyTest) # # # == Test Suite # # As more and more unit tests accumulate for a given project, it # becomes a real drag running them one at a time, and it also # introduces the potential to overlook a failing test because you # forget to run it. Suddenly it becomes very handy that the # TestRunners can take any object that returns a Test::Unit::TestSuite # in response to a suite method. The TestSuite can, in turn, contain # other TestSuites or individual tests (typically created by a # TestCase). In other words, you can easily wrap up a group of # TestCases and TestSuites like this: # # require 'test/unit/testsuite' # require 'tc_myfirsttests' # require 'tc_moretestsbyme' # require 'ts_anothersetoftests' # # class TS_MyTests # def self.suite # suite = Test::Unit::TestSuite.new # suite << TC_MyFirstTests.suite # suite << TC_MoreTestsByMe.suite # suite << TS_AnotherSetOfTests.suite # return suite # end # end # Test::Unit::UI::Console::TestRunner.run(TS_MyTests) # # Now, this is a bit cumbersome, so Test::Unit does a little bit more # for you, by wrapping these up automatically when you require # 'test/unit'. What does this mean? It means you could write the above # test case like this instead: # # require 'test/unit' # require 'tc_myfirsttests' # require 'tc_moretestsbyme' # require 'ts_anothersetoftests' # # Test::Unit is smart enough to find all the test cases existing in # the ObjectSpace and wrap them up into a suite for you. It then runs # the dynamic suite using the console TestRunner. # # # == Questions? # # I'd really like to get feedback from all levels of Ruby # practitioners about typos, grammatical errors, unclear statements, # missing points, etc., in this document (or any other). # module Unit # If set to false Test::Unit will not automatically run at exit. def self.run=(flag) @run = flag end # Automatically run tests at exit? def self.run? @run ||= false end end end at_exit do unless $! || Test::Unit.run? exit Test::Unit::AutoRunner.run end end