add a few more nodes

tests/node_tests/level_rotate.py

@@ -0,0 +1,37 @@
+import numpy as np
+from tests.node_tests._shared import make_field
+
+
+def test_level_rotate_removes_tilt():
+    from backend.nodes.level_rotate import LevelRotate
+
+    node = LevelRotate()
+    y, x = np.mgrid[:64, :64].astype(np.float64)
+    data = 2.0 * x + 3.0 * y
+    field = make_field(data=data)
+
+    (result,) = node.process(field)
+    assert result.data.shape == data.shape
+    assert result.data.std() < data.std() * 0.25
+
+
+def test_level_rotate_preserves_shape():
+    from backend.nodes.level_rotate import LevelRotate
+
+    node = LevelRotate()
+    data = np.random.default_rng(42).standard_normal((48, 48))
+    field = make_field(data=data)
+
+    (result,) = node.process(field)
+    assert result.data.shape == (48, 48)
+
+
+def test_level_rotate_flat_noop():
+    from backend.nodes.level_rotate import LevelRotate
+
+    node = LevelRotate()
+    data = np.ones((32, 32)) * 7.0
+    field = make_field(data=data)
+
+    (result,) = node.process(field)
+    assert np.allclose(result.data, 7.0, atol=1e-6)