ci: run doctest in CI for Python API examples (delta-io#1840)

.github/workflows/python_build.yml

@@ -118,7 +118,7 @@ jobs:
       - name: Run tests
         run: |
           source venv/bin/activate
-          python -m pytest -m '((s3 or azure) and integration) or not integration and not benchmark'
+          python -m pytest -m '((s3 or azure) and integration) or not integration and not benchmark' --doctest-modules
 
       - name: Test without pandas
         run: |

python/Makefile

@@ -75,7 +75,7 @@ check-python: ## Run check on Python
 .PHONY: unit-test
 unit-test: ## Run unit test
 	$(info --- Run Python unit-test ---)
-	python -m pytest
+	python -m pytest --doctest-modules 
 
 .PHONY: test-pyspark
 test-pyspark:

python/conftest.py

@@ -0,0 +1,20 @@
+import os
+import pathlib
+
+import pytest
+
+
+@pytest.fixture(autouse=True)
+def doctest_setup(
+    request: pytest.FixtureRequest,
+    monkeypatch: pytest.MonkeyPatch,
+    tmp_path: pathlib.Path,
+):
+    if isinstance(request.node, pytest.DoctestItem):
+        # disable color for doctests so we don't have to include
+        # escape codes in docstrings
+        monkeypatch.setitem(os.environ, "NO_COLOR", "1")
+        # Explicitly set the column width
+        monkeypatch.setitem(os.environ, "COLUMNS", "80")
+        # Work in a temporary directory
+        monkeypatch.chdir(str(tmp_path))