diff --git a/python/crankshaft/crankshaft/poc/xyz.py b/python/crankshaft/crankshaft/poc/xyz.py
index 4e32596..558c77c 100644
--- a/python/crankshaft/crankshaft/poc/xyz.py
+++ b/python/crankshaft/crankshaft/poc/xyz.py
@@ -2,4 +2,5 @@ import plpy
 
 def xyz():
     plpy.notice('XYZ...')
-    return "xyz-result"
+    r = plpy.execute("SELECT * FROM table")
+    return r[0]['x']
diff --git a/python/crankshaft/test/mock_plpy.py b/python/crankshaft/test/mock_plpy.py
new file mode 100644
index 0000000..63c88f6
--- /dev/null
+++ b/python/crankshaft/test/mock_plpy.py
@@ -0,0 +1,34 @@
+import re
+
+class MockPlPy:
+    def __init__(self):
+        self._reset()
+
+    def _reset(self):
+        self.infos = []
+        self.notices = []
+        self.debugs = []
+        self.logs = []
+        self.warnings = []
+        self.errors = []
+        self.fatals = []
+        self.executes = []
+        self.results = []
+        self.prepares = []
+        self.results = []
+
+    def _define_result(self, query, result):
+        pattern = re.compile(query, re.IGNORECASE | re.MULTILINE)
+        self.results.append([pattern, result])
+
+    def notice(self, msg):
+        self.notices.append(msg)
+
+    def info(self, msg):
+        self.infos.append(msg)
+
+    def execute(self, query): # TODO: additional arguments
+       for result in self.results:
+          if result[0].match(query):
+            return result[1]
+       return []
diff --git a/python/crankshaft/test/test_poc.py b/python/crankshaft/test/test_poc.py
index 06fc3d6..7307285 100644
--- a/python/crankshaft/test/test_poc.py
+++ b/python/crankshaft/test/test_poc.py
@@ -3,14 +3,17 @@
 
 import unittest
 
-class MockPlPy:
-    def notice(self, msg):
-        print msg
+from mock_plpy import MockPlPy
+plpy = MockPlPy()
 
 import sys
-sys.modules['plpy'] = MockPlPy()
+sys.modules['plpy'] = plpy
+
 import crankshaft
 
 class TestPoc(unittest.TestCase):
     def test_should_have_xyz(self):
-        assert crankshaft.poc.xyz() == "xyz-result"
+        plpy._reset()
+        plpy._define_result('select\s+\*\s+from\s+table', [{'x': 111}])
+        assert crankshaft.poc.xyz() == 111
+        assert plpy.notices[0] == 'XYZ...'