Move checks into a Python file.

Signed-off-by: Tim 'mithro' Ansell <me@mith.ro>

Author: mithro

Makefile.template

@@ -26,4 +26,4 @@ example-command: | $(CONDA_ENV_PYTHON)
 
 # Check that no system packages are found in the environment.
 test-command: | $(CONDA_ENV_PYTHON)
-	$(IN_CONDA_ENV) python -c "import sys; assert all('/usr' not in p for p in sys.path), sys.path; print(sys.path)"
+	$(IN_CONDA_ENV) python check.py

test/check.py

@@ -0,0 +1,6 @@
+#!/usr/bin/env python
+
+# Check that no system packages are found in the environment.
+import sys
+assert all('/usr' not in p for p in sys.path), sys.path
+print(sys.path)