doc: update test README (issue #3)

README.md

@@ -91,17 +91,14 @@ path/to/batsim -p test/platforms/monocore/2machines.xml \
 
 After the execution, you should see the [Batsim outputs](https://batsim.readthedocs.io/en/latest/tuto-result-analysis/tuto.html) in the output directory.
 
-## Run tests
+## Run the tests
 Batmen has a set of integration tests, located in the `test` directory. To run all the tests:
 
 ```bash
-nix-shell -A test
-pytest
+nix-shell -A test --command "pytest"
 ```
 
-For single tests: `pytest -k EXPRESSION` only runs the tests matching the given substring expression. 
-
-Open `test-out/test_report.html` in a browser to see the test results.
+For more information about the tests, read the [test README](test/README.md)
 
 [Nix]: https://nixos.org/nix/
 [Batsim]: https://batsim.org/

test/README.md

 # Batmen tests
 
-### Extra dependencies
-Some tests use a tool from the external library `batmen-tools` developped separately. To update it to the latest version:
+## Run the tests
+We use [Nix] to enter an environment with all the dependencies.
 
-```bash
-cd test
-curl -O https://gitlab.irit.fr/sepia-pub/mael/batmen-tools/-/raw/main/distance_batsim_output.py
-```
+### `batmen` manually compiled
+This will run the test suite with the version of `batmen` located in the folder `build/`
 
-### Running tests
 ``` bash
-nix-shell ../default.nix -A test --command 'pytest'
-# or just pytest, but you must prepare your env...
+nix-shell ../default.nix -A test
+pytest
 ```
 
-Optionally, use Batsim's binary cache to avoid recompiling many things (e.g., SimGrid).
+### Recompile automatically
+If you want Nix to recompile `batmen` before entering the environment:
 
 ``` bash
-nix-env -iA cachix -f https://cachix.org/api/v1/install # installs cachix
-cachix use batsim # add Batsim's cachix storage as a Nix remote cache
+nix-shell ../default.nix -A test_rebuild
+pytest
 ```
 
-### How does it work?
+### Browse the test outputs
+Instead of reading the (long) outputs from the terminal, you can open `test-out/test_report.html` in a browser to see the test results.
+
+### Run an individual test
+`pytest -k EXPRESSION` only runs the tests matching the given substring expression.
+
+For example, `pytest -k user` will only run the tests whose name contain "user".
+
+## How does the testing work?
+pytest interprets all the functions starting with `test_` as tests. For one of these functions: 
+
 0. nix-shell puts you into an environment where batsched, batsim, robin, redis, etc. are available (code in [default.nix])
 1. pytest generates combinations of test input (code in [conftest.py])
-2. for each combination of inputs: (code in [test_runner.py])
+2. for each combination of inputs:
   1. pytest generates a [robin] input file
-  2. pytest generates batsim and batsched input files if needed
+  2. pytest generates batsim and batmen input files if needed
   3. pytest executes [robin] or [robintest] on the generated file
 
-### Running a specific test
+Finally, we have special tests (in the file [test_zexpected_output.py](./test_zexpected_output.py)) verifying that the output of the previous tests correspond to the expected output. 
+
+## Running a failed test
 You can manually rerun a test with robin:
 ```
 robin test-instances/FAILING-TEST.yaml
@@ -42,8 +52,17 @@ You can also run batsim and batsched in different terminals:
 ./test-out/FAILING-TEST/cmd/sched.bash
 ```
 
+## Extra dependency
+Some tests use a tool from the library `batmen-tools` developped separately. To do update it to the latest version:
+
+```bash
+cd batmen/test
+curl -O https://gitlab.irit.fr/sepia-pub/mael/batmen-tools/-/raw/main/distance_batsim_output.py
+```
+
 [default.nix]: ../default.nix
 [conftest.py]: ./conftest.py
 [test_runner.py]: ./test_runner.py
 [robin]: https://framagit.org/batsim/batexpe
 [robintest]: https://framagit.org/batsim/batexpe
+[Nix]: https://nixos.org/nix/
\ No newline at end of file