allow control over pytest concurrency

Author: rauchy

Makefile

@@ -27,8 +27,9 @@ lint:
 test:
 	pytest -m 'not integration and not benchmark' --cov=databricks --cov-report html tests
 
+PYTEST_CONCURRENCY ?= auto
 integration:
-	pytest -n auto -m 'integration and not benchmark' --reruns 2 --dist loadgroup --cov=databricks --cov-report html tests
+	pytest -n $(PYTEST_CONCURRENCY) -m 'integration and not benchmark' --reruns 2 --dist loadgroup --cov=databricks --cov-report html tests
 
 benchmark:
 	pytest -m 'benchmark' tests