add a few more nodes

tests/node_tests/unrotate.py

@@ -0,0 +1,50 @@
+import numpy as np
+from tests.node_tests._shared import make_field
+
+
+def test_unrotate_preserves_shape():
+    from backend.nodes.unrotate import Unrotate
+
+    node = Unrotate()
+    data = np.random.default_rng(42).standard_normal((64, 64))
+    field = make_field(data=data)
+
+    (result,) = node.process(field, symmetry="4-fold")
+    assert result.data.shape == (64, 64)
+
+
+def test_unrotate_small_angle():
+    from backend.nodes.unrotate import Unrotate, _slope_angle_histogram, _find_dominant_angle
+
+    y, x = np.mgrid[:128, :128].astype(np.float64)
+    angle_deg = 3.0
+    angle_rad = np.radians(angle_deg)
+    data = np.sin(2 * np.pi * (x * np.cos(angle_rad) + y * np.sin(angle_rad)) / 20.0)
+
+    hist = _slope_angle_histogram(data)
+    correction = _find_dominant_angle(hist, 4)
+    assert abs(np.degrees(correction)) < 10.0
+
+
+def test_unrotate_no_rotation_passthrough():
+    from backend.nodes.unrotate import Unrotate
+
+    node = Unrotate()
+    y, x = np.mgrid[:64, :64].astype(np.float64)
+    data = np.sin(2 * np.pi * x / 16.0)
+    field = make_field(data=data)
+
+    (result,) = node.process(field, symmetry="4-fold")
+    assert np.allclose(result.data, data, atol=0.1)
+
+
+def test_unrotate_symmetry_options():
+    from backend.nodes.unrotate import Unrotate
+
+    node = Unrotate()
+    data = np.random.default_rng(99).standard_normal((64, 64))
+    field = make_field(data=data)
+
+    for sym in ["2-fold", "3-fold", "4-fold", "6-fold"]:
+        (result,) = node.process(field, symmetry=sym)
+        assert result.data.shape == (64, 64)