The integration tests of CPM.cmake are written in Ruby. They use a custom integration test framework which extends the [Test::Unit](https://www.rubydoc.info/github/test-unit/test-unit/Test/Unit) library.
The current working directory doesn't matter. If you are in `<repo-root>/test/integration`, you can run simply `$ ruby runner.rb`.
You can execute with `--help` (`$ ruby runner.rb --help`) to see various configuration options of the runner like running individual tests or test cases, or ones that match a regex.
The tests themselves are situated in the Ruby scripts prefixed with `test_`. `<repo-root>/test/integration/test_*`. You can also run an individual test script. For example to only run the **basics** test case, you can execute `$ ruby test_basics.rb`
The tests generate CMake scripts and execute CMake and build toolchains. By default they do this in a directory they generate in your temp path (`/tmp/cpm-test/` on Linux). You can configure the working directory of the tests with an environment variable `CPM_INTEGRATION_TEST_DIR`. For example `$ CPM_INTEGRATION_TEST_DIR=~/mycpmtest; ruby runner.rb`
## Writing tests
Writing tests makes use of the custom integration test framework in `lib.rb`. It is a relatively small extension of Ruby's Test::Unit library.
### The Gist
* Tests cases are Ruby scripts in this directory. The file names must be prefixed with `test_`
* The script should `require_relative './lib'` to allow for individual execution (or else if will only be executable from the runner)
* A test case file should contain a single class which inherits from `IntegrationTest`. It *can* contain multiple classes, but that's bad practice as it makes individual execution harder and implies a dependency between the classes.
* There should be no dependency between the test scripts. Each should be executable individually and the order in which multiple ones are executed mustn't matter.
* The class should contain methods, also prefixed with `test_` which will be executed by the framework. In most cases there would be a single test method per class.
* In case there are multiple test methods, they will be executed in the order in which they are defined.
