(#18) Added a fixture for accessing data files

Added a new fixture for using data files on test cases that
require generating/validating execution against 'model' data.

tests/papi/test_lz4.py

@@ -1,4 +1,23 @@
+from __future__ import unicode_literals
+from distutils import dir_util
 from pytest import fixture
+from os import path
+
+
+@fixture
+def datadir(tmpdir, request):
+    '''
+    Fixture responsible for searching a folder with the same name of test
+    module and, if available, moving all contents to a temporary directory so
+    tests can use them freely.
+    '''
+    filename = request.module.__file__
+    test_dir, _ = path.splitext(filename)
+
+    if path.isdir(test_dir):
+        dir_util.copy_tree(test_dir, bytes(tmpdir))
+
+    return tmpdir
 
 @fixture
 def lz4():