Add Runner interface.

testing/util.py

@@ -0,0 +1,29 @@
+
+import os
+import os.path
+import shutil
+
+
+TESTING_DIR = os.path.abspath(os.path.dirname(__file__))
+
+
+def get_resource_path(path):
+    return os.path.join(TESTING_DIR, 'resources', path)
+
+
+def copy_tree_to_path(src_dir, dest_dir):
+    """Copies all of the things inside src_dir to an already existing dest_dir.
+
+    This looks eerily similar to shutil.copytree, but copytree has no option
+    for not creating dest_dir.
+    """
+    names = os.listdir(src_dir)
+
+    for name in names:
+        srcname = os.path.join(src_dir, name)
+        destname = os.path.join(dest_dir, name)
+
+        if os.path.isdir(srcname):
+            shutil.copytree(srcname, destname)
+        else:
+            shutil.copy(srcname, destname)