diff --git a/docs/src/developers.md b/docs/src/developers.md
index a1326a85..0ead48c8 100644
--- a/docs/src/developers.md
+++ b/docs/src/developers.md
@@ -39,4 +39,42 @@ To create a new libtrixi release, follow these steps:
    whether the current state of the repository is identical to the latest release or not.  
    The next development version is obtained by increasing the *patch* number and appending
    `-pre`. For example, if you just released version `v0.1.1`, the next development version
-   would be `v0.1.2-pre`.
\ No newline at end of file
+   would be `v0.1.2-pre`.
+
+
+## Testing
+
+### Testing the C interface
+
+For testing the C interface of libtrixi we rely on [GoogleTest](https://google.github.io/googletest).
+The tests are contained in `cpp`-files located under `test/c`. They are processed by `cmake` and made available via
+`ctest`, provided the options
+```
+-DENABLE_TESTING=ON -DJULIA_PROJECT_PATH=<libtrixi-julia_directory>
+```
+are passed to `cmake` during configuration.
+The executables can then be found under `<build_directory>/test/c` (they will not be installed). To run them, execute
+```
+ctest [-V] [-R <regex>]
+```
+from `<build_directory>/test/c` or the top-level directory `<build_directory>`.
+The optional argument `-V` turns on verbose output, and `-R` lets you specify a regular expression to select specific tests.
+A list of available tests can be obtained via `ctest -N`.
+
+### Testing the Fortran interface
+
+For testing the Fortran interface of libtrixi we rely on [test-drive](https://github.com/fortran-lang/test-drive),
+which integrates with `cmake` and `ctest` as well. The tests are contained in `f90`-files under `test/fortran`. Usage is
+analogous to the C interface.
+
+### Testing the Julia interface
+
+For testing the Julia interface of libtrixi, which is contained in the Julia package `LibTrixi.jl`, we rely on
+[Julia's testing infrastructure](https://docs.julialang.org/en/v1/stdlib/Test/). There is a dedicated test project,
+located under `LibTrixi.jl/test`, which contains `runtest.jl` and further `jl`-files containing the actual tests.
+Invoke via
+```
+JULIA_DEPOT_PATH=<julia-depot_directory> \
+LIBTRIXI_DEBUG=all \
+    julia --project=./LibTrixi.jl -e 'import Pkg; Pkg.test()'
+```