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Diffstat (limited to 'doc/manual/src/contributing')
| -rw-r--r-- | doc/manual/src/contributing/testing.md | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/doc/manual/src/contributing/testing.md b/doc/manual/src/contributing/testing.md index ccd90088e..1b15d12b1 100644 --- a/doc/manual/src/contributing/testing.md +++ b/doc/manual/src/contributing/testing.md @@ -3,13 +3,25 @@ ## Unit-tests The unit-tests for each Nix library (`libexpr`, `libstore`, etc..) are defined -under `src/{library_name}/tests` using the +under `tests/unit/{library_name}/tests` using the [googletest](https://google.github.io/googletest/) and [rapidcheck](https://github.com/emil-e/rapidcheck) frameworks. You can run the whole testsuite with `make check`, or the tests for a specific component with `make libfoo-tests_RUN`. Finer-grained filtering is also possible using the [--gtest_filter](https://google.github.io/googletest/advanced.html#running-a-subset-of-the-tests) command-line option, or the `GTEST_FILTER` environment variable. +### Unit test support libraries + +There are headers and code which are not just used to test the library in question, but also downstream libraries. +For example, we do [property testing] with the [rapidcheck] library. +This requires writing `Arbitrary` "instances", which are used to describe how to generate values of a given type for the sake of running property tests. +Because types contain other types, `Arbitrary` "instances" for some type are not just useful for testing that type, but also any other type that contains it. +Downstream types frequently contain upstream types, so it is very important that we share arbitrary instances so that downstream libraries' property tests can also use them. + +It is important that these testing libraries don't contain any actual tests themselves. +On some platforms they would be run as part of every test executable that uses them, which is redundant. +On other platforms they wouldn't be run at all. + ## Functional tests The functional tests reside under the `tests/functional` directory and are listed in `tests/functional/local.mk`. |