STY: Check pytest.raises is used context manager (pandas-dev#24332)

ci/code_checks.sh

@@ -148,6 +148,15 @@ if [[ -z "$CHECK" || "$CHECK" == "patterns" ]]; then
     invgrep -R --exclude=*.pyc --exclude=testing.py --exclude=test_testing.py assert_raises_regex pandas
     RET=$(($RET + $?)) ; echo $MSG "DONE"
 
+    # Check that we use pytest.raises only as a context manager
+    #
+    # For any flake8-compliant code, the only way this regex gets
+    # matched is if there is no "with" statement preceding "pytest.raises"
+    MSG='Check for pytest.raises as context manager (a line starting with `pytest.raises` is invalid, needs a `with` to precede it)' ; echo $MSG
+    MSG='TODO: This check is currently skipped because so many files fail this. Please enable when all are corrected (xref gh-24332)' ; echo $MSG
+    # invgrep -R --include '*.py' -E '[[:space:]] pytest.raises' pandas/tests
+    # RET=$(($RET + $?)) ; echo $MSG "DONE"
+
     MSG='Check that no file in the repo contains tailing whitespaces' ; echo $MSG
     invgrep --exclude="*.svg" -RI "\s$" *
     RET=$(($RET + $?)) ; echo $MSG "DONE"