Merge branch 'bugfix/153-test' into msvccompiler

distutils/tests/test_ccompiler.py

@@ -0,0 +1,55 @@
+import os
+import sys
+import platform
+import textwrap
+import sysconfig
+
+import pytest
+
+from distutils import ccompiler
+
+
+def _make_strs(paths):
+    """
+    Convert paths to strings for legacy compatibility.
+    """
+    if sys.version_info > (3, 8) and platform.system() != "Windows":
+        return paths
+    return list(map(os.fspath, paths))
+
+
+@pytest.fixture
+def c_file(tmp_path):
+    c_file = tmp_path / 'foo.c'
+    gen_headers = ('Python.h',)
+    is_windows = platform.system() == "Windows"
+    plat_headers = ('windows.h',) * is_windows
+    all_headers = gen_headers + plat_headers
+    headers = '\n'.join(f'#include <{header}>\n' for header in all_headers)
+    payload = (
+        textwrap.dedent(
+            """
+        #headers
+        void PyInit_foo(void) {}
+        """
+        )
+        .lstrip()
+        .replace('#headers', headers)
+    )
+    c_file.write_text(payload)
+    return c_file
+
+
+def test_set_include_dirs(c_file):
+    """
+    Extensions should build even if set_include_dirs is invoked.
+    In particular, compiler-specific paths should not be overridden.
+    """
+    compiler = ccompiler.new_compiler()
+    python = sysconfig.get_paths()['include']
+    compiler.set_include_dirs([python])
+    compiler.compile(_make_strs([c_file]))
+
+    # do it again, setting include dirs after any initialization
+    compiler.set_include_dirs([python])
+    compiler.compile(_make_strs([c_file]))