Party hard, test harder — DJ Testo
Testo is a test framework for OCaml that takes inspiration from its predecessor Alcotest and from pytest. Features include:
- support for explicit XFAIL tests i.e. tests that are expected to fail, indicating that they should be fixed eventually;
- support for test snapshots i.e. persistent storage of captured stdout or stderr;
- reviewing and approving tests without re-running them;
- nested test suites;
- various ways to select tests;
- parallel execution (using multiprocessing);
- supports OCaml >= 4.08.
Like with Alcotest, a test executable is generated from a list of tests
written in OCaml. The function to interpret the command line
and run things is Testo.interpret_argv.
The core subcommands supported by a test executable are:
run: run testsstatus: check the status of the tests without re-running themapprove: approve test output and make it the new reference
A test is fundamentally a name and test function of type
unit -> unit. A test is considered successful if the test function
returns normally and is considered failed if it raises an exception.
A test is created with Testo.create which takes a variety of options
in addition to the name and the test function.
Testo doesn't provide a library for writing assertions. Using the
Alcotest
module for this is recommended. For example,
checking that some test result res equals an expected value of 42
is written as:
Alcotest.(check int) "equal" 42 res;This raises an exception that is turned into a nice error message.
