Add allocation test for cvnp

Author: virtuald

subprojects/robotpy-cscore/tests/test_cv.py

@@ -7,3 +7,12 @@ def test_empty_img():
     sink = cs.CvSink("something")
     _, rimg = sink.grabFrame(img)
     assert (rimg == img).all()
+
+
+def test_nonempty_img():
+    img = np.zeros(shape=(480, 640, 3), dtype=np.uint8)
+    img2 = np.zeros(shape=(480, 640, 3), dtype=np.uint8)
+    sink = cs.CvSink("something")
+    _, img = sink.grabFrame(img)
+    _, img = sink.grabFrame(img)
+    assert (img == img2).all()