Regression test
===============

:unified-context-diff: https://en.wikipedia.org/wiki/Diff#Unified_format

Source structure
----------------

----------------------------------------------
.
├── unit
│   └── …
└── compose
    └── …
        ├── [enabled]    → applicability
        ├── [env]        → environment setup
        ├── [rc]         → configuration
        ├── [in]         → start file
        ├── cmd          → command
        ├── [script]     → UI automation
        ├── [out]        → expected end file
        ├── [kak_*]      → expected expansion values
        └── [error]      → expected error
----------------------------------------------

Usage
-----

To test, just type +run [test]+ in the +test+ directory.
It will print each passing test.  If a test fails, a {unified-context-diff}[unified context diff]
is printed showing the test’s expected output and the actual output.

Details
-------

+enabled+ is optional.
If it exists and is executable,
it is invoked with no parameters.
If it exits with a non-zero exit code,
the test is assumed to be not applicable to the current environment
(for example, a test for OS-specific integration
isn't useful on a different OS)
and will be silently skipped.

+env+ is optional.
If it exists, it will be sourced before starting Kakoune.

+rc+ is optional
and should contain a sequence of commands,
_e.g._, +set-option+, +define-command+, +declare-option+.
+rc+ is sourced and evaluated before the +cmd+ key sequence is executed.

+in+ is optional
and should contain the initial text loaded into the input buffer
for editing by the +cmd+ key sequence.

+cmd+ is required
and should contain a key sequence that will edit the input buffer.
+cmd+ is executed after the +rc+ command sequence is sourced.

+script+ is optional
and is a shell-script that will be sourced after +cmd+ is executed.
The special +ui_in+ function sends a string
(expected to be a JSON UI message,
see `doc/json_ui.asciidoc` in the Kakoune source)
to the running Kakoune instance,
while the special +ui_out+ function
checks the next JSON UI messages from Kakoune
against its arguments,
and fails the test if any of them are different.

You can also say `ui_out -ignore N` to ignore the next _N_ JSON UI messages,
where _N_ is a positive integer. 

+out+ is optional
and should contain the expected text generated by the +cmd+ key sequence.

If the actual +out+ text
does not match the expected content in the corresponding file,
the unit test will fail.

If there is no +out+
then the unit test will always succeed.

Any +kak_*+ files should match the corresponding expansion
after +cmd+ is complete.
For example, a file named +kak_selection_desc+
should match the +%val{selection_desc}+ expansion.
See `:doc expansions` for a list of available expansions.

If there is an +error+ file,
the test is expected to produce an error.
If Kakoune exits successfully,
or if it fails with the wrong error,
the test is marked as a failure.