Use data model fixture for tests.

Makefile

 PROJECT = yangson
+.PHONY = tags deps install-deps test
 
 tags:
 	find $(PROJECT) -name "*.py" | etags -
@@ -8,3 +9,6 @@ deps:
 
 install-deps:
 	pip install -r requirements.txt
+
+test:
+	@py.test tests

tests/test_turing.py

+import pytest
 from yangson import DataModel
 
-def test_turing():
+@pytest.fixture
+def data_model():
     tdir = "examples/turing/"
     with open(tdir + "yang-library.json", encoding="utf-8") as ylfile:
         ylib = ylfile.read()
-    dm = DataModel.from_yang_library(ylib, tdir)
-    top = dm.get_data_node("/turing-machine:turing-machine")
-    assert top.name == "turing-machine"
-    assert top.ns == "turing-machine"
+    return DataModel.from_yang_library(ylib, tdir)
+        
+def test_top(data_model):
+    top = data_model.get_data_node("/turing-machine:turing-machine")
+    assert top.qname == "turing-machine:turing-machine"