Updated docs on how to run tests.

README.md

@@ -70,12 +70,30 @@ with Flow(...) as flow:
 
 ## How to test
 
+There are two test suites: unit tests and integration tests. Integration tests are prepared to plug to some of our
+AWS resources, hence they are not fully reliable since they require specific credentials and permissions. The 
+recommended policy is:
+
+- Use the unit tests in any CI process you want.
+- Use the unit tests frequently as you code.
+- Do not use the integration tests in CI processes.
+- Use the integration tests as milestone checks when finishing feature branches.
+- Make sure to ensure integration tests are working before making a new release.
+
+When building new tests, please keep this philosophy in mind.
+
+
 IDE-agnostic:
 
 1. Set up a virtual environment which contains both `lolafect` and the dependencies listed in `requirements-dev.txt`.
-2. Run: `pytests tests`
+2. Run:
+   - For all tests: `pytests tests`
+   - Only unit tests: `pytest tests/test_unit`
+   - Only integration tests: `pytest tests/test_integration`
 
 In Pycharm:
 
 - If you configure `pytest` as the project test runner, Pycharm will most probably autodetect the test
-  folder and allow you to run the test suite within the IDE.
+  folder and allow you to run the test suite within the IDE. However, Pycharm has troubles running the integration 
+  tests since the shell it runs from does not have the AWS credentials. Hence, for now we recommend you to only use 
+  the Pycharm integrated test runner for the unit tests. You can easily set up a Run Configuration for that.