Bulked out table test a bit

I'm closing #50 - more tests will be added in the future, but the framework
is neatly in place for them now.

tests/test_app.py

@@ -44,6 +44,13 @@ def test_table_page(three_table_app_client):
     data = response.json
     assert data['query']['sql'] == 'select * from "simple_primary_key" order by pk limit 51'
     assert data['query']['params'] == {}
+    assert data['rows'] == [{
+        'pk': '1',
+        'content': 'hello',
+    }, {
+        'pk': '2',
+        'content': 'world',
+    }]
 
 
 THREE_TABLES = '''