diff --git a/mkdocs/tests/build_tests.py b/mkdocs/tests/build_tests.py
index 1861ba3b..fa29bf6b 100644
--- a/mkdocs/tests/build_tests.py
+++ b/mkdocs/tests/build_tests.py
@@ -227,8 +227,11 @@ class BuildTests(PathAssertionMixin, unittest.TestCase):
     @mock.patch('mkdocs.utils.write_file')
     @mock.patch('mkdocs.commands.build._build_template', return_value='some content')
     @mock.patch('gzip.GzipFile')
-    def test_build_sitemap_template(self, mock_gzip_gzipfile, mock_build_template, mock_write_file):
-        cfg = load_config()
+    @tempdir()
+    def test_build_sitemap_template(
+        self, site_dir, mock_gzip_gzipfile, mock_build_template, mock_write_file
+    ):
+        cfg = load_config(site_dir=site_dir)
         env = cfg['theme'].get_env()
         build._build_theme_template('sitemap.xml', env, mock.Mock(), cfg, mock.Mock())
         mock_write_file.assert_called_once()
@@ -265,9 +268,10 @@ class BuildTests(PathAssertionMixin, unittest.TestCase):
 
     # Test build._build_extra_template
 
+    @tempdir()
     @mock.patch('mkdocs.commands.build.open', mock.mock_open(read_data='template content'))
-    def test_build_extra_template(self):
-        cfg = load_config()
+    def test_build_extra_template(self, site_dir):
+        cfg = load_config(site_dir=site_dir)
         fs = [
             File('foo.html', cfg['docs_dir'], cfg['site_dir'], cfg['use_directory_urls']),
         ]
diff --git a/mkdocs/tests/plugin_tests.py b/mkdocs/tests/plugin_tests.py
index 29a13546..80c8231b 100644
--- a/mkdocs/tests/plugin_tests.py
+++ b/mkdocs/tests/plugin_tests.py
@@ -11,7 +11,7 @@ from mkdocs.config import base
 from mkdocs.config import config_options as c
 from mkdocs.config.base import ValidationError
 from mkdocs.exceptions import Abort, BuildError, PluginError
-from mkdocs.tests.base import load_config
+from mkdocs.tests.base import load_config, tempdir
 
 
 class _DummyPluginConfig(base.Config):
@@ -222,7 +222,8 @@ class TestPluginCollection(unittest.TestCase):
         with self.assertRaises(KeyError):
             collection.run_event('unknown', 'page content')
 
-    def test_run_build_error_event(self):
+    @tempdir()
+    def test_run_build_error_event(self, site_dir):
         build_errors = []
 
         class PluginRaisingError(plugins.BasePlugin):
@@ -251,27 +252,27 @@ class TestPluginCollection(unittest.TestCase):
             def on_build_error(self, error, **kwargs):
                 build_errors.append(error)
 
-        cfg = load_config()
+        cfg = load_config(site_dir=site_dir)
         cfg['plugins']['errorplugin'] = PluginRaisingError(error_on='pre_page')
         with self.assertLogs('mkdocs', level='ERROR'):
             self.assertRaises(Abort, build.build, cfg)
 
-        cfg = load_config()
+        cfg = load_config(site_dir=site_dir)
         cfg['plugins']['errorplugin'] = PluginRaisingError(error_on='page_markdown')
         with self.assertLogs('mkdocs', level='ERROR'):
             self.assertRaises(Abort, build.build, cfg)
 
-        cfg = load_config()
+        cfg = load_config(site_dir=site_dir)
         cfg['plugins']['errorplugin'] = PluginRaisingError(error_on='page_content')
         with self.assertLogs('mkdocs', level='ERROR'):
             self.assertRaises(Abort, build.build, cfg)
 
-        cfg = load_config()
+        cfg = load_config(site_dir=site_dir)
         cfg['plugins']['errorplugin'] = PluginRaisingError(error_on='post_page')
         with self.assertLogs('mkdocs', level='ERROR'):
             self.assertRaises(ValueError, build.build, cfg)
 
-        cfg = load_config()
+        cfg = load_config(site_dir=site_dir)
         cfg['plugins']['errorplugin'] = PluginRaisingError(error_on='')
         build.build(cfg)