test: do not rely on external resources

Use buildout testing utility to start a webserver instead of downloading
from the internet.
This also fixes the test because the downloaded content changed.

slapos/recipe/cmmi/tests.py

@@ -226,17 +226,26 @@ class NonInformativeTests(unittest.TestCase):
         self.assertFalse(is_temp)
         self.assertEqual(file, url)
 
-        url = 'ftp://ftp.gnu.org/welcome.msg'
+        tmpdir = tempfile.mkdtemp()
+        self.addCleanup(shutil.rmtree, tmpdir)
+
+        with open(os.path.join(tmpdir, 'hello.txt'), 'w') as f:
+            f.write('Hello\n')
+        # This file md5sum is 09f7e02f1290be211da707a266f153b3
+
+        port = zc.buildout.testing.start_server(tmpdir)
+
+        url = 'http://localhost:%s/hello.txt' % port
         file, is_temp = recipe.download_file(url)
         self.assertTrue(is_temp)
         self.assertTrue(os.path.exists(file))
 
-        url = 'ftp://ftp.gnu.org/welcome.msg#0de362e544463d298ebb2c5d00a84698'
+        url = 'http://localhost:%s/hello.txt#09f7e02f1290be211da707a266f153b3' % port
         file, is_temp = recipe.download_file(url)
         self.assertTrue(is_temp)
         self.assertTrue(os.path.exists(file))
 
-        url = 'ftp://ftp.gnu.org/welcome.msg#0205'
+        url = 'http://localhost:%s/hello.txt#0205' % port
         self.assertRaises(zc.buildout.download.ChecksumError, recipe.download_file, url)
 
     def test_buildout_prefix(self):