Run tests as part of CI (#59)

Closes #53.

This PR adds a workflow that runs the test suite every Saturday and every time commits are pushed to open PRs or to the master and dev branches. In the interest of green computing, it is only triggered if these commits change at least one of these files:
- any `.py` file
- the workflow itself, i.e., `.github/workflows/test_suite.yml`
- `pyproject.toml` so that we can test the installation

Deleted `test_oggm_compat.py` since all tests fail anyway.

Author: ddundo

.github/workflows/test_suite.yml

@@ -0,0 +1,49 @@
+name: 'Install PyGEM and Run Test Suite'
+
+on:
+  push:
+    branches:
+      - master
+      - dev
+    paths:
+      - '**.py'
+      - '.github/workflows/test_suite.yml'
+      - 'pyproject.toml'
+
+  pull_request:
+    paths:
+      - '**.py'
+      - '.github/workflows/test_suite.yml'
+      - 'pyproject.toml'
+
+  # Run test suite every Saturday at 1AM GMT (1 hour after the Docker image is updated)
+  schedule:
+    - cron: '0 1 * * 6'
+
+# Stop the workflow if a new one is started
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  test_suite:
+    name: 'Test suite'
+    runs-on: ubuntu-latest
+
+    # Use pygem:latest for master branch and pygem:dev otherwise
+    container:
+      image: ghcr.io/pygem-community/pygem:${{ github.ref == 'refs/heads/master' && 'latest' || 'dev' }}
+      options: --user root
+
+    steps:
+      - name: 'Checkout the repo'
+        id: checkout
+        uses: actions/checkout@v4
+
+      - name: 'Reinstall PyGEM'
+        run: pip install --break-system-packages -e .
+
+      - name: 'Run tests'
+        run: |
+          python3 -m coverage erase
+          python3 -m pytest --cov=pygem -v --durations=20 pygem/tests

pygem/tests/test_oggm_compat.py

@@ -34,6 +34,8 @@ jupyter = "^1.1.1"
 arviz = "^0.20.0"
 oggm = "^1.6.2"
 ruamel-yaml = "^0.18.10"
+pytest = ">=8.3.4"
+pytest-cov = ">=6.0.0"
 
 [tool.poetry.scripts]
 initialize = "pygem.bin.op.initialize:main"
@@ -53,4 +55,9 @@ duplicate_gdirs = "pygem.bin.op.duplicate_gdirs:main"
 
 [build-system]
 requires = ["poetry-core"]
-build-backend = "poetry.core.masonry.api"
+build-backend = "poetry.core.masonry.api"
+
+[tool.coverage.report]
+omit = ["pygem/tests/*"]
+show_missing = true
+skip_empty = true