Document tests dependencies (#565)

* Add hint to README to install dev requirements before running tests

* Improve tests README

tests/README.MD

@@ -1,11 +1,24 @@
+# Tests
+
 ## Pre-reqs
-Make sure you have `pytest` and `pydantic` installed:
-`pip install pytest pydantic`
+
+Make sure you have venv activated:
+
+```bash
+source ../venv/bin/activate
+```
+
+Make sure you have the required dev dependencies installed:
+
+```bash
+python3 -m pip install -r ../requirements-dev.txt
+```
 
 We assume that your green-metrics-tool is already set up to work on your machine, as it will use your local config.yml
 file to determine which metric providers can be utilized in the tests.
 
 ## First time setup
+
 run:
 
 `python3 setup-test-env.py`
@@ -18,6 +31,7 @@ You will need to re-run this setup script if new metric providers are added or t
 significant way.
 
 ## Running
+
 To run the tests, you need to first start the test containers, then run pytest, and afterwards stop the containers.
 There are a few scripts to make this easy.
 
@@ -33,4 +47,4 @@ window run the pytest suite using `pytest`, and then stop the containers when yo
 Running a subset of tests using pytest is better explained within the documentation here:
  https://docs.pytest.org/en/7.2.x/how-to/usage.html
 
-You can also do everything in one command using the `./run-tests.sh` script.
+You can also do everything in one command using the `./run-tests.sh` script.