improve back and frontend testing

tests/node_tests/mask_invert.py

@@ -15,3 +15,21 @@ def test_mask_invert():
 
     double, = node.process(inverted)
     assert np.array_equal(double, mask)
+
+
+def test_mask_invert_with_field():
+    from backend.nodes.mask_invert import MaskInvert
+    from backend.execution_context import active_node, execution_callbacks
+    from tests.node_tests._shared import make_field
+
+    node = MaskInvert()
+    mask = np.zeros((32, 32), dtype=np.uint8)
+    mask[8:24, 8:24] = 255
+    field = make_field(data=np.ones((32, 32)))
+
+    previews = []
+    with execution_callbacks(preview=lambda nid, d: previews.append(d)), active_node("test"):
+        inverted, = node.process(mask, field=field)
+    assert inverted.dtype == np.uint8
+    assert len(previews) == 1
+    assert previews[0].startswith("data:image/png;base64,")