Add GET /user/ implementation that works

Previously my GET was just a placeholder so I could build URIs against
it. Now it actually works and returns information on a user

tests/api/test_user.py

@@ -2,6 +2,8 @@ import json
 
 import pytest
 
+import vanth.platform.user
+
 
 @pytest.mark.usefixtures('db')
 def test_post(client):
@@ -13,3 +15,13 @@ def test_post(client):
     response = client.post('/user/', data=json.dumps(data))
     assert response.status_code == 204
     assert response.headers['Location']
+
+@pytest.mark.usefixtures('db')
+def test_get(client):
+    location = vanth.platform.user.create('Blue Stahli', 'blue@stahli.com', 'metamorphosis')
+    response = client.get(location)
+    assert response.status_code == 200
+    assert response.json == {
+        'name'      : 'Blue Stahli',
+        'username'  : 'blue@stahli.com',
+    }