CONTRIBUTING.md: Improve codestyle and testing section (#376)

Previously, the section "Codestyle and Testing"
was outdated, still from the time where there was
only the SDK inside this repository.

This greatly extends the section, renaming it to
"Code Quality" and introducing subsections for
"Codestyle" and "Testing", where we describe how
to run the necessary tests locally on the
developer's machine for each of the packages
inside this monorepository.

Fixes #353

Author: s-heppner

CONTRIBUTING.md

@@ -119,16 +119,41 @@ The following guidelines are for the commit or PR message text:
   via `https://link/to.pdf#Page=123`
 - Optionally, where applicable reference respective issues: `Fixes #123`
 
-## Codestyle and Testing
+## Code Quality
 
+The Eclipse BaSyx Python project emphasizes high code quality.
+To achieve this, we apply best practices where possible and have developed an extensive suite of tests that are 
+expected to pass for each Pull Request to the project. 
+
+### Codestyle
 Our code follows the [PEP 8 -- Style Guide for Python Code](https://www.python.org/dev/peps/pep-0008/)
 with the following exceptions:
 - Line length is allowed to be up to 120 characters, though lines up to 100 characters are preferred.
 
 Additionally, we use [PEP 484 -- Type Hints](https://www.python.org/dev/peps/pep-0484/) throughout the code to enable type checking the code.
 
-Before submitting any changes, make sure to let `mypy` and `pycodestyle` check your code and run the unit tests with
-Python's builtin `unittest`. To install the required tools, use:
+Before submitting any changes to the SDK, make sure to let `mypy` and `pycodestyle` check your code and run the unit 
+tests with Python's builtin `unittest`. 
+
+### Testing
+There are many automated checks implemented in the CI pipelines of this project, all of which are expected to pass 
+before new code can be added:
+
+- We check that the Python packages can be built.
+- We run the developed unittests and aim for a code coverage of at least 80%.
+- We perform static code analysis for type-checking and codestyle, not just in the code itself, but also in codeblocks 
+  that are inside docstrings and the `README.md`.
+- We check that the automatically generated developer documentation compiles.
+- We check that the Python Versions we support match between the different subprojects in the monorepository and are 
+  not End of Life.
+- We check that the year in the copyright headers in each file (stemming from the license) is correct.
+
+> [!note]
+> We strongly suggest to run the tests locally, before submitting a Pull Request, in order to accelerate the review 
+> process. 
+
+### Testing the SDK
+For testing the SDK locally on your machine, you can install the required tools like so:
 ```bash
 pip install .[dev]
 ```
@@ -142,12 +167,51 @@ Running all checks:
 mypy basyx test
 pycodestyle --max-line-length 120 basyx test
 python -m unittest
+coverage run --source basyx --branch -m unittest
+coverage report -m
 ```
 
-We aim to cover our code with test by at least 80%. To check test coverage, you can use `coverage`:
+We aim to cover our code with tests by at least 80%.
+
+This should help you sort out the most important bugs in your code.
+Note that there are more checks that run in the CI once you open a Pull Request.
+If you want to run the additional checks, please refer to the [CI definition](./.github/workflows/ci.yml).
 
+### Testing the Server
+Currently, the automated server tests are still under development. 
+To test that the server is working, we expect to at least be able to build the docker images and run a container
+of it without error. 
+
+For that, you need to have Docker installed on your system. 
+In the directory with the `Dockerfile`: 
 ```bash
-pip install coverage
+docker build -t basyx-python-server .
+docker run --name basyx-python-server basyx-python-server
+```
+Wait until you see the line:
+```
+INFO success: quit_on_failure entered RUNNING state
+```
+
+### Testing the Compliance Tool
+For the Compliance Tool, you can install the required tools like this (from the `./compliance_tool` directory):
+```bash
+pip install -e ../sdk[dev]
+pip install .[dev]
+```
+The first line installs the SDK and its dependencies, the second the developer dependencies for the compliance tool
+itself.
+
+Then you can run the checks via:
+```bash
+mypy basyx test
+pycodestyle --max-line-length 120 basyx test
+python -m unittest
 coverage run --source basyx --branch -m unittest
 coverage report -m
 ```
+
+We aim to cover our code with tests by at least 80%.
+This should help you sort out the most important bugs in your code.
+Note that there are more checks that run in the CI once you open a Pull Request.
+If you want to run the additional checks, please refer to the [CI definition](./.github/workflows/ci.yml).