Fixes a bug that prevents openml from finding the config file (#651)

* Fixes a bug that prevents openml from finding the config file

* add mini test

Author: joaquinvanschoren

openml/config.py

@@ -24,7 +24,7 @@
     'connection_n_retries': 2,
 }
 
-config_file = os.path.expanduser(os.path.join('~', '.openml' 'config'))
+config_file = os.path.expanduser(os.path.join('~', '.openml', 'config'))
 
 # Default values are actually added here in the _setup() function which is
 # called at the end of this module

tests/test_openml/test_config.py

@@ -0,0 +1,11 @@
+import os
+
+import openml.config
+import openml.testing
+
+
+class TestConfig(openml.testing.TestBase):
+
+    def test_config_loading(self):
+        self.assertTrue(os.path.exists(openml.config.config_file))
+        self.assertTrue(os.path.isdir(os.path.expanduser('~/.openml')))