Use fixtures for the symlink tests to fix appveyor

testing/resources/broken_symlink

@@ -1 +0,0 @@
-does_not_exist

testing/resources/working_symlink

@@ -1 +0,0 @@
-does_exist

tests/check_symlinks_test.py

@@ -3,16 +3,21 @@ import os
 import pytest
 
 from pre_commit_hooks.check_symlinks import check_symlinks
-from testing.util import get_resource_path
 
 
-@pytest.mark.xfail(os.name == 'nt', reason='No symlink support on windows')
+xfail_symlink = pytest.mark.xfail(os.name == 'nt', reason='No symlink support')
+
+
+@xfail_symlink
 @pytest.mark.parametrize(
-    ('filename', 'expected_retval'), (
+    ('dest', 'expected'), (('exists', 0), ('does-not-exist', 1)),
-        ('broken_symlink', 1),
-        ('working_symlink', 0),
-    ),
 )
-def test_check_symlinks(filename, expected_retval):
+def test_check_symlinks(tmpdir, dest, expected):  # pragma: no cover (symlinks)
-    ret = check_symlinks([get_resource_path(filename)])
+    tmpdir.join('exists').ensure()
-    assert ret == expected_retval
+    symlink = tmpdir.join('symlink')
+    symlink.mksymlinkto(tmpdir.join(dest))
+    assert check_symlinks((symlink.strpath,)) == expected
+
+
+def test_check_symlinks_normal_file(tmpdir):
+    assert check_symlinks((tmpdir.join('f').ensure().strpath,)) == 0