CI: specify python version and activate env (#888)

* CI: specify python version and activate env

* CI: use source activate instead of conda activate

* CI: specify shell

* CI: specify path for activate

* CI: merge activate and install steps

* CI: use env variable for conda path

.github/workflows/unit-tests.yml

@@ -16,22 +16,40 @@ concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}
   cancel-in-progress: true
 
+env:
+  CONDA_PATH: /opt/conda/
+
 jobs:
   build:
 
+    name: ${{ matrix.python.name }} unit tests
     runs-on: ubuntu-latest
-    container: ghcr.io/bilby-dev/bilby-python311:latest
+    container: ghcr.io/bilby-dev/bilby-python${{ matrix.python.short-version }}:latest
     strategy:
       fail-fast: false
+      matrix:
+        python:
+          - name: Python 3.10
+            version: 3.10
+            short-version: 310
+          - name: Python 3.11
+            version: 3.11
+            short-version: 311
+          - name: Python 3.12
+            version: 3.12
+            short-version: 312
 
     steps:
     - uses: actions/checkout@v3
     - name: Install package
       run: |
+        # activate env so that conda list shows the correct environment
+        source $CONDA_PATH/bin/activate python${{ matrix.python.short-version }}
         # FIXME: Remove this line when gwpy supports matplotlib 3.10
         conda install -c conda-forge "matplotlib<3.10"
         python -m pip install .
         conda list --show-channel-urls
+      shell: bash
     # - name: Run precommits
     #   run: |
     #     pre-commit run --all-files --verbose --show-diff-on-failure