low pri features

tests/node_tests/lattice_measurement.py

@@ -0,0 +1,46 @@
+import numpy as np
+import pytest
+from tests.node_tests._shared import make_field
+
+
+def test_lattice_acf_returns_outputs():
+    from backend.nodes.lattice_measurement import LatticeMeasurement
+
+    node = LatticeMeasurement()
+    field = make_field(shape=(64, 64))
+    corr, records = node.process(field, "acf")
+    assert corr.data.shape == (64, 64)
+    assert isinstance(records, list)
+
+
+def test_lattice_fft_returns_outputs():
+    from backend.nodes.lattice_measurement import LatticeMeasurement
+
+    node = LatticeMeasurement()
+    field = make_field(shape=(64, 64))
+    corr, records = node.process(field, "fft")
+    assert corr.data.shape == (64, 64)
+
+
+def test_lattice_detects_periodic_structure():
+    """A simple cosine grid should produce lattice measurements."""
+    from backend.nodes.lattice_measurement import LatticeMeasurement
+
+    node = LatticeMeasurement()
+    x = np.linspace(0, 4 * np.pi, 64, endpoint=False)
+    X, Y = np.meshgrid(x, x)
+    data = np.cos(X) + np.cos(Y)
+    field = make_field(data=data)
+
+    corr, records = node.process(field, "acf")
+    # Should detect at least one vector
+    assert len(records) >= 3
+
+
+def test_lattice_unknown_method():
+    from backend.nodes.lattice_measurement import LatticeMeasurement
+
+    node = LatticeMeasurement()
+    field = make_field(shape=(32, 32))
+    with pytest.raises(ValueError):
+        node.process(field, "unknown")