Tests pass on windows

testing/resources/system_hook_with_spaces_repo/hooks.yaml

@@ -1,5 +1,5 @@
 -   id: system-hook-with-spaces
     name: System hook with spaces
-    entry: /usr/bin/python -c 'import sys; print("Hello World")'
+    entry: bash -c 'echo "Hello World"'
     language: system
     files: \.sh$

testing/util.py

@@ -49,8 +49,27 @@ def is_valid_according_to_schema(obj, schema):
         return False
 
 
-def skipif_slowtests_false(func):
-    return pytest.mark.skipif(
-        os.environ.get('slowtests') == 'false',
-        reason='slowtests=false',
-    )(func)
+skipif_slowtests_false = pytest.mark.skipif(
+    os.environ.get('slowtests') == 'false',
+    reason='slowtests=false',
+)
+
+xfailif_windows_no_ruby = pytest.mark.xfail(
+    os.name == 'nt',
+    reason='Ruby support not yet implemented on windows.',
+)
+
+xfailif_windows_no_node = pytest.mark.xfail(
+    os.name == 'nt',
+    reason='Node support not yet implemented on windows.',
+)
+
+
+def platform_supports_pcre():
+    return cmd_output('grep', '-P', '', os.devnull, retcode=None)[0] == 1
+
+
+xfailif_no_pcre_support = pytest.mark.xfail(
+    not platform_supports_pcre(),
+    reason='grep -P is not supported on this platform',
+)