Add tests for image tags.

skimage/io/tests/test_image.py

@@ -0,0 +1,17 @@
+from skimage.io import Image
+
+from numpy.testing import assert_equal, assert_array_equal
+
+def test_tags():
+    f = Image([1, 2, 3], foo='bar', sigma='delta')
+    g = Image([3, 2, 1], sun='moon')
+    h = Image([1, 1, 1])
+
+    assert_equal(f.tags['foo'], 'bar')
+    assert_array_equal((g + 2).tags['sun'], 'moon')
+    assert_equal(h.tags, {})
+
+if __name__ == "__main__":
+    from numpy.testing import run_module_suite
+    run_module_suite()
+