[JTH] add pytest to dependencies in tests

Author: tausiaj

.github/workflows/python-tests.yml

@@ -30,7 +30,7 @@ jobs:
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip
-          pip install .[all]
+          pip install .[all,tests]
 
       - name: Lint
         run: |

pyproject.toml

@@ -51,6 +51,7 @@ dependencies = [
 
 [project.optional-dependencies]
 docs = ["sphinx", "sphinx-rtd-theme", "jupyter-sphinx", "myst-parser"]
+tests = ["pytest", "ruff"]
 downloaders = ["cdsapi", "ecmwf-opendata"]
 waves = ["wavespectra", "olas"]
 numerical-models = ["hydromt-sfincs"]