diff --git a/scrapy/tests/test_downloadermiddleware_defaultheaders.py b/scrapy/tests/test_downloadermiddleware_defaultheaders.py
new file mode 100644
index 000000000..cd1624eb4
--- /dev/null
+++ b/scrapy/tests/test_downloadermiddleware_defaultheaders.py
@@ -0,0 +1,30 @@
+from unittest import TestCase
+
+from scrapy.conf import settings
+from scrapy.contrib.downloadermiddleware.defaultheaders import DefaultHeadersMiddleware
+from scrapy.http import Response, Request
+from scrapy.spider import BaseSpider
+
+
+class TestDefaultHeadersMiddleware(TestCase):
+
+    def setUp(self):
+        self.spider = BaseSpider()
+        self.mw = DefaultHeadersMiddleware()
+        self.default_headers = dict([(k, [v]) for k, v in \
+            settings.get('DEFAULT_REQUEST_HEADERS').iteritems()])
+
+    def test_process_request(self):
+        req = Request('http://www.scrapytest.org')
+        self.mw.process_request(req, self.spider)
+        self.assertEquals(req.headers, self.default_headers)
+
+    def test_update_headers(self):
+        headers = {'Accept-Language': ['es'], 'Test-Header': ['test']}
+        req = Request('http://www.scrapytest.org', headers=headers)
+        self.assertEquals(req.headers, headers)
+
+        self.mw.process_request(req, self.spider)
+        self.default_headers.update(headers)
+        self.assertEquals(req.headers, self.default_headers)
+
diff --git a/scrapy/tests/test_downloadermiddleware_stats.py b/scrapy/tests/test_downloadermiddleware_stats.py
new file mode 100644
index 000000000..fb117614b
--- /dev/null
+++ b/scrapy/tests/test_downloadermiddleware_stats.py
@@ -0,0 +1,39 @@
+from unittest import TestCase
+
+from scrapy.conf import settings
+from scrapy.contrib.downloadermiddleware.stats import DownloaderStats
+from scrapy.http import Request, Response
+from scrapy.spider import BaseSpider
+from scrapy.stats import stats
+
+
+class TestDownloaderStats(TestCase):
+
+    def setUp(self):
+        self.spider = BaseSpider()
+        self.spider.domain_name = 'scrapytest.org'
+        self.mw = DownloaderStats()
+
+        stats.open_domain(self.spider.domain_name)
+
+        self.req = Request('scrapytest.org')
+        self.res = Response('scrapytest.org', status=400)
+
+    def test_process_request(self):
+        self.mw.process_request(self.req, self.spider)
+        self.assertEqual(stats.get_value('downloader/request_count', \
+            domain=self.spider.domain_name), 1)
+        
+    def test_process_response(self):
+        self.mw.process_response(self.req, self.res, self.spider)
+        self.assertEqual(stats.get_value('downloader/response_count', \
+            domain=self.spider.domain_name), 1)
+
+    def test_process_exception(self):
+        self.mw.process_exception(self.req, Exception(), self.spider)
+        self.assertEqual(stats.get_value('downloader/exception_count', \
+            domain=self.spider.domain_name), 1)
+
+    def tearUp(self):
+        stats.close_domain(self.spider.domain_name)
+