Add model tests.

Author: jonathanrocher

ets_tutorial/__init__.py

@@ -4,25 +4,33 @@
 import numpy as np
 
 # ETS imports
-from traits.api import Dict, File, HasStrictTraits, observe
+from traits.api import cached_property, Dict, File, HasStrictTraits, Property
 
 
 class ImageFile(HasStrictTraits):
     """ Model to hold an image file.
     """
     filepath = File
 
-    metadata = Dict
+    metadata = Property(Dict, depends_on="filepath")
 
     def to_array(self):
+        if not self.filepath:
+            return np.array([])
+
         with PIL.Image.open(self.filepath) as img:
             return np.asarray(img)
 
-    @observe("filepath")
-    def load_metadata(self, event):
+    @cached_property
+    def _get_metadata(self):
+        if not self.filepath:
+            return {}
+
         with PIL.Image.open(self.filepath) as img:
             exif = img._getexif()
 
         if exif:
-            self.metadata = {TAGS[k]: v for k, v in exif.items()
-                             if k in TAGS}
+            return {TAGS[k]: v for k, v in exif.items()
+                    if k in TAGS}
+        else:
+            return {}

stage4.1_first_application/pycasa/model/image_file.py

@@ -0,0 +1,30 @@
+from os.path import dirname, join
+from unittest import TestCase
+
+import numpy as np
+from numpy.testing import assert_array_equal
+
+from pycasa.model.image_file import ImageFile
+
+import ets_tutorial
+
+TUTORIAL_DIR = dirname(ets_tutorial.__file__)
+
+SAMPLE_IMG_DIR = join(TUTORIAL_DIR, "..", "sample_images")
+
+SAMPLE_IMG1 = join(SAMPLE_IMG_DIR, "IMG-0311_xmas_2020.JPG")
+
+
+class TestImageFile(TestCase):
+    def test_no_image_file(self):
+        img = ImageFile()
+        self.assertEqual(img.metadata, {})
+        data = img.to_array()
+        self.assertIsInstance(data, np.ndarray)
+        self.assertEqual(data.shape, (0,))
+
+    def test_image_metadata(self):
+        img = ImageFile(filepath=SAMPLE_IMG1)
+        self.assertNotEqual(img.metadata, {})
+        data = img.to_array()
+        self.assertEqual(data.shape, (768, 1024, 3))