tests: improve testing by splitting tests + use six for basestring python3 compatibility

jsignature/tests/fields.py

@@ -1,4 +1,5 @@
 import json
+import six
 from django.test import SimpleTestCase
 from django.core.exceptions import ValidationError
 
@@ -8,35 +9,49 @@ from ..forms import JSignatureField as JSignatureFormField
 
 class JSignatureFieldTest(SimpleTestCase):
 
-    def test_to_python(self):
+    def test_to_python_empty(self):
         f = JSignatureField()
-        # Empty values
         for val in ['', [], '[]']:
             self.assertIsNone(f.to_python(val))
-        # Correct values
+
+    def test_to_python_correct_value_python(self):
+        f = JSignatureField()
         val = [{"x": [1, 2], "y": [3, 4]}]
         self.assertEquals(val, f.to_python(val))
+
+    def test_to_python_correct_value_json(self):
+        f = JSignatureField()
+        val = [{"x": [1, 2], "y": [3, 4]}]
         val_str = '[{"x":[1,2], "y":[3,4]}]'
         self.assertEquals(val, f.to_python(val_str))
-        # Incorrect values
+
+    def test_to_python_incorrect_value(self):
+        f = JSignatureField()
         val = 'foo'
         self.assertRaises(ValidationError, f.to_python, val)
 
-    def test_get_prep_value(self):
+    def test_get_prep_value_empty(self):
         f = JSignatureField()
-        # Empty values
         for val in ['', [], '[]']:
             self.assertIsNone(f.get_prep_value(val))
-        # Correct values
+
+    def test_get_prep_value_correct_values_python(self):
+        f = JSignatureField()
         val = [{"x": [1, 2], "y": [3, 4]}]
         val_prep = f.get_prep_value(val)
-        self.assertIsInstance(val_prep, basestring)
+        self.assertIsInstance(val_prep, six.string_types)
         self.assertEquals(val, json.loads(val_prep))
+
+    def test_get_prep_value_correct_values_json(self):
+        f = JSignatureField()
+        val = [{"x": [1, 2], "y": [3, 4]}]
         val_str = '[{"x":[1,2], "y":[3,4]}]'
         val_prep = f.get_prep_value(val_str)
-        self.assertIsInstance(val_prep, basestring)
+        self.assertIsInstance(val_prep, six.string_types)
         self.assertEquals(val, json.loads(val_prep))
-        # Incorrect values
+
+    def test_get_prep_value_incorrect_values(self):
+        f = JSignatureField()
         val = type('Foo')
         self.assertRaises(ValidationError, f.get_prep_value, val)