Test on many versions in CI

Author: PeterJCLaw

.circleci/config.yml

@@ -1,37 +1,79 @@
 version: 2.1
 
+references:
+  install-poetry: &install-poetry
+    run:
+      name: Install Poetry
+      command: |
+        curl -sSL https://raw.githubusercontent.com/python-poetry/poetry/master/get-poetry.py | python
+  restore-dependencies-cache: &restore-dependencies-cache
+    restore_cache:
+      keys:
+        - deps-py<< parameters.python-version >>-django<< parameters.django-version >>-{{ checksum "poetry.lock" }}
+  install-dependencies: &install-dependencies
+    run:
+      name: Install Dependencies
+      command: |
+        source $HOME/.poetry/env
+        poetry install
+        poetry run pip install "django~=<< parameters.django-version >>.0"
+  save-dependencies-cache: &save-dependencies-cache
+    save_cache:
+      key: deps-py<< parameters.python-version >>-django<< parameters.django-version >>-{{ checksum "poetry.lock" }}
+      paths:
+        - /home/circleci/.cache/pypoetry/virtualenvs
+  parametrised-python-executor: &parametrised-python-executor
+    parameters:
+      python-version:
+        type: string
+      django-version:
+        type: string
+    executor:
+      name: python
+      version: << parameters.python-version >>
+  version-matrix: &version-matrix
+    matrix:
+      parameters:
+        python-version: ["3.5.5", "3.6", "3.7"]
+        django-version: ["2.2", "3.0", "3.1", "3.2"]
+      exclude:
+        - python-version: "3.5.5"
+          django-version: "3.0"
+        - python-version: "3.5.5"
+          django-version: "3.1"
+        - python-version: "3.5.5"
+          django-version: "3.2"
+
+executors:
+  python:
+    parameters:
+      version:
+        type: string
+    docker:
+      - image: circleci/python:<< parameters.version >>
+
 jobs:
   build-test:
-    docker:
-      - image: circleci/python:3.5.5
+    <<: *parametrised-python-executor
+
     steps:
       - checkout
-      - run:
-          name: Install Poetry
-          command: |
-            curl -sSL https://raw.githubusercontent.com/python-poetry/poetry/master/get-poetry.py | python
-      - restore_cache:
-          keys:
-            - deps-{{ checksum "poetry.lock" }}
-      - run:
-          name: Install Dependencies
-          command: |
-            source $HOME/.poetry/env
-            poetry install
-      - save_cache:
-          key: deps-{{ checksum "poetry.lock" }}
-          paths:
-            - /home/circleci/.cache/pypoetry/virtualenvs
+
+      - *install-poetry
+      - *restore-dependencies-cache
+      - *install-dependencies
+      - *save-dependencies-cache
 
       - run:
-          name: Build
+          name: Run Tests
           command: |
             source $HOME/.poetry/env
             poetry run ./runtests
 
   deploy:
-    docker:
-      - image: circleci/python:3.5.5
+    executor:
+      name: python
+      version: "3.7"
     steps:
       - checkout
       - run:
@@ -44,16 +86,21 @@ jobs:
               --username "${PYPI_USERNAME}" \
               --password "${PYPI_PASSWORD}" \
               --no-interaction
+
 workflows:
   version: 2.1
 
   build-test:
     jobs:
-      - build-test
+      - build-test:
+          name: build-test-py<< matrix.python-version >>-Django<< matrix.django-version >>
+          <<: *version-matrix
 
   build-test-deploy:
     jobs:
       - build-test:
+          name: build-test-py<< matrix.python-version >>-Django<< matrix.django-version >>
+          <<: *version-matrix
           filters:
             tags:
               only: /v[0-9]+(\.[0-9]+)*/