Merge pull request #24 from r-burns/darwin

Fix test_read_cmake_files on macOS

.github/workflows/tests.yml

@@ -1,6 +1,6 @@
 name: Tests
 
-on: [push]
+on: [push, pull_request]
 
 jobs:
   build:

tests/test_api.py

@@ -41,6 +41,8 @@ def test_read_cmake_files(cmake_build):
         assert 'GNU' in api.get_variable_doc('CMAKE_CXX_COMPILER_ID')
     elif system == 'Windows':
         assert 'MSVC' in api.get_variable_doc('CMAKE_CXX_COMPILER_ID')
+    elif system == 'Darwin':
+        assert 'Clang' in api.get_variable_doc('CMAKE_CXX_COMPILER_ID')
     else:
         raise RuntimeError('Unexpected system')