In earlier posts, Passing the result from ‘foreach’ and Passing the result from ‘setup’, I showed how to (awkwardly) pass the result from the setup function to the test functions.

If you’re using erlang.mk, you can run a single unit test suite with make eunit t=whatever. That’s no good if you want to run multiple test suites. Here’s a nasty hack that makes it possible.

In several of the previous posts, for example Using ‘setup’, I’ve started a server in suite_setup/0 and needed to kill it in suite_cleanup/1. I showed a simple way to do that, but it’s not the best. Here’s a better way to do it.

Similar to passing the result from {setup, Setup, ... to each test, you can also pass the result from {foreach, Setup, ... to each test, but there are some differences.

The result from setup is passed to cleanup already. What if we want to pass it to each of our tests? It’s a bit awkward, but it looks like the following:

If you want to run some setup before (and cleanup after) a list of tests, and also some setup and cleanup for each test, you can nest setup and foreach:

We saw that setup runs setup/cleanup before all tests in a list. If you want to run some setup/cleanup before each test in a list, you can use foreach:

What if we want to run some setup before a set of tests (and cleanup afterwards)?

While you could specify each test with a single function, you can also use a test “instantiator” (or generator) and have it return a list.

A simple EUnit test might look like this:

Some examples of how to use Erlang’s unit-testing framework, EUnit. Starting with simple examples and getting more advanced.

For when you want to run both per-suite and per-test setup and cleanup in eunit tests.

You’ve got an Erlang module with a private (not-exported) function, and you want to add some unit tests for that function? How should you do that?