Enhance README with setup and testing instructions

README.md

@@ -1,3 +1,62 @@
 # Keystone Python Client
 
-Official Python client for the Keystone API.
+The official Python client for the Keystone API.
+
+A quickstart guide for project developers is provided below.
+For the full Keystone project documentation, see [keystone.bhpc.dev](https://keystone.bhpc.dev).
+
+## Developer Setup
+
+This project uses the [Poetry](https://python-poetry.org/) package manager.
+To initialize a new environment, start by defining your desired Python interpreter:
+
+```bash
+poetry env use python3
+```
+
+Next, install the project and its dependencies.
+The `dev` dependency group is optional, but includes useful utilities for running application tests:
+
+```bash
+poetry install --with dev
+```
+
+## Common Tasks
+
+### Running Tests
+
+Application tests are organized by testing strategy.
+Unit tests are used to verify components in isolation and require no external services.
+Function tests validate package integration against a live API server and require a running Keystone API instance.
+
+#### Unit Tests
+
+Unit tests are executed using the standard `unittest` library:
+
+```bash
+python -m unittest discover -s ./tests/unit_tests
+```
+
+Alternatively, the `coverage` utility can also be used to execute tests and report the resulting coverage:
+
+```bash
+coverage run -m unittest discover -s ./tests/unit_tests
+coverage report
+```
+
+#### Function Tests
+
+Function tests are used to validate the client against a running API server.
+The following environmental variables are used to configure connection settings against the upstream API:
+
+| Variable            | Description                                       | Default                 |
+|---------------------|---------------------------------------------------|-------------------------|
+| `TEST_API_HOST`     | URL of the Keystone API instance to test against. | `http://localhost:8000` |
+| `TEST_API_USER`     | Username used to authenticate with the API.       | `admin`                 |
+| `TEST_API_PASSWORD` | Password used to authenticate with the API.       | `quickstart`            |
+
+Once the target API instance is configured and running, function tests are executed using the standard library `unittest` framework:
+
+```bash
+python -m unittest discover -s ./tests/function_tests
+```