Merge pull request #64 from felix-seifert/felix-seifert/description-o…

…f-tests

Describe how our tests can interfere with development and might require updates

DEVELOPING.md

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+# Dev Guide
+
+## Automated Tests
+
+Before merging any PR into our `main` branch, we run automated tests on your modified source code. Besides some platform
+independent unit tests, several of these tests are platform dependent and require to be executed remotely on the GitHub
+build agents. These tests generate roadmaps on different OSs with your modified code and compare them to how these 
+roadmaps should look like.
+
+All the required tests are triggered automatically once you open or change a PR. To verify that the `main` branch hosts
+a correct version of the code, any merge to the `main` branch also triggers the tests.
+
+### Change Example Roadmaps
+
+Usually, the appearance of the newly generated roadmaps should not change between different releases of `Roadmapper`.
+However, some code changes purposefully change the appearance of the generated roadmaps. To let our tests succeed with
+the new version, we will then have to generate new example roadmaps on the GitHub build agents which accommodate these
+changes.
+
+To generate these example roadmaps on different GitHub build agents, we have the manual workflow
+[generate_examples](.github/workflows/generate_examples.yaml). We can trigger it manually through the
+[Actions tab](https://github.com/csgoh/roadmapper/actions/workflows/generate_examples.yaml). In the dropdown to trigger
+a run of the workflow, we can also select on which branch the workflow should run, i.e. we can influence which code 
+should be used to generate the example roadmaps.
+
+As we usually want to generate new example roadmaps for code which is not present on the `main` branch, we have to run
+the workflow on the branch where the respective code changes are present. When ran, the workflow produces artifacts for
+the different platforms which contain the example roadmaps. These artifacts can be found in the summary of the 
+respective workflow run. To use these new example roadmaps, we should download them and commit them manually to the 
+directory [`src/tests/example_roadmaps`](src/tests/example_roadmaps).