Checkpoint 7

tests/test_obs.py

@@ -0,0 +1,71 @@
+"""Observation builder — shape, normalisation, order invariance."""
+
+import math
+
+import numpy as np
+import pytest
+
+from herding.perception.obs import OBS_DIM, build_obs
+
+
+def test_obs_shape_and_dtype():
+    obs = build_obs((0.0, 0.0), 0.0, [(5.0, 5.0)], [False])
+    assert obs.shape == (OBS_DIM,)
+    assert obs.dtype == np.float32
+
+
+def test_obs_no_active_sheep_terminal():
+    # All sheep penned → flock-summary fields zero, count zero.
+    obs = build_obs((0.0, 0.0), 0.0, [(1.0, 1.0), (2.0, 2.0)], [True, True])
+    assert obs[19] == 0.0
+    # Aggregate fields (CoM, radius, std, vectors) should all be zero.
+    assert np.allclose(obs[4:12], 0.0)
+
+
+def test_obs_dog_pose_normalised():
+    obs = build_obs((15.0, -15.0), math.pi / 2, [(0.0, 0.0)], [False])
+    assert math.isclose(obs[0], 1.0)
+    assert math.isclose(obs[1], -1.0)
+    assert math.isclose(obs[2], math.cos(math.pi / 2), abs_tol=1e-6)
+    assert math.isclose(obs[3], math.sin(math.pi / 2), abs_tol=1e-6)
+
+
+def test_obs_order_invariance():
+    """Sheep order in the input list must not affect the observation."""
+    sheep = [(3.0, 2.0), (-5.0, 1.0), (0.0, 8.0)]
+    p = [False] * 3
+    a = build_obs((0.0, 0.0), 0.0, sheep, p)
+    b = build_obs((0.0, 0.0), 0.0, list(reversed(sheep)), list(reversed(p)))
+    assert np.allclose(a, b)
+
+
+def test_obs_count_field_normalised_by_n_max():
+    sheep = [(1.0, 1.0)] * 5
+    p = [False] * 5
+    obs = build_obs((0.0, 0.0), 0.0, sheep, p, n_max=10)
+    assert math.isclose(obs[19], 0.5)
+
+
+def test_obs_polar_histogram_sums_to_one():
+    sheep = [(1.0, 0.0), (-1.0, 0.0), (0.0, 1.0), (0.0, -1.0)]
+    obs = build_obs((0.0, 0.0), 0.0, sheep, [False] * 4)
+    assert math.isclose(float(obs[20:28].sum()), 1.0, abs_tol=1e-6)
+
+
+def test_obs_named_channels_closest_rearmost():
+    # Channels 28..29 = (closest_to_pen - dog) / 15
+    # Channels 30..31 = (rearmost - dog) / 15
+    pen_x, pen_y = 11.5, -15.0
+    near = (pen_x + 1.0, pen_y + 1.0)
+    far = (-10.0, 10.0)
+    obs = build_obs((0.0, 0.0), 0.0, [near, far], [False, False])
+    tol = 1e-5
+    assert math.isclose(obs[28], near[0] / 15.0, abs_tol=tol)
+    assert math.isclose(obs[29], near[1] / 15.0, abs_tol=tol)
+    assert math.isclose(obs[30], far[0] / 15.0, abs_tol=tol)
+    assert math.isclose(obs[31], far[1] / 15.0, abs_tol=tol)
+
+
+def test_obs_pen_vector_zero_at_pen_entry():
+    obs = build_obs((11.5, -15.0), 0.0, [(0.0, 0.0)], [False])
+    assert math.isclose(obs[14], 0.0)         # distance to pen