start functional testing

tests/support.py

@@ -0,0 +1,18 @@
+from contextlib import contextmanager
+
+from tempfile import mkdtemp
+from shutil import rmtree
+
+
+@contextmanager
+def temporary_folder():
+    """creates a temporary folder, return it and delete it afterwards.
+
+    This allows to do something like this in tests:
+
+        >>> with temporary_folder() as d:
+            # do whatever you want
+    """
+    tempdir = mkdtemp()
+    yield tempdir
+    rmtree(tempdir)