with a glass of water

tests/test_metadata.py

@@ -0,0 +1,83 @@
+import pytest
+import numpy as np
+from dodgeballtracker.metadata import (VideoMetadata, KnownImagePoint,
+                                       BirdViewPoint, KnownPoint)
+
+
+@pytest.fixture
+def simple_transformation_matrix() -> np.matrix:
+    m = np.matrix([[2, 1], [1, 1]])
+    assert np.linalg.det(m) > 0.1
+    return m
+
+
+def create_know_point(v, m) -> KnownPoint:
+    u = (m @ v).A[0]
+    return KnownPoint(image=KnownImagePoint.from_vec(v),
+                      bird_view=BirdViewPoint.from_vec(u))
+
+
+@pytest.fixture
+def four_known_points(simple_transformation_matrix: np.matrix) -> list[
+    KnownPoint]:
+    return [
+        create_know_point([x, y], simple_transformation_matrix)
+        for x in [-100, 100]
+        for y in [-100, 100]
+    ]
+
+
+@pytest.fixture
+def eight_known_points(simple_transformation_matrix: np.matrix,
+                       four_known_points: list[KnownPoint]) -> list[KnownPoint]:
+    return [
+        create_know_point([x, y], simple_transformation_matrix)
+        for x in [-50, 50]
+        for y in [-50, 50]
+    ] + four_known_points
+
+
+
+@pytest.fixture
+def simple_video_metadata(four_known_points) -> VideoMetadata:
+    return VideoMetadata(knownPoints=four_known_points)
+
+@pytest.fixture
+def mega_video_metadata(eight_known_points) -> VideoMetadata:
+    return VideoMetadata(knownPoints=eight_known_points)
+
+@pytest.fixture
+def broken_video_metadata(four_known_points) -> VideoMetadata:
+    return VideoMetadata(knownPoints=four_known_points[:2])
+
+
+def test_get_view_perspective_matrix(simple_video_metadata: VideoMetadata) -> None:
+    m = simple_video_metadata.get_view_perspective_matrix()
+    expt = np.array([
+        [200, 100, 0],
+        [100, 100, 0],
+        [0, 0, 1]
+    ])
+    np.testing.assert_array_almost_equal(m, expt)
+
+
+@pytest.mark.xfail
+def test_get_view_perspective_matrix_mega(mega_video_metadata: VideoMetadata) -> None:
+    """
+    The issue with this test is that the transformation
+    matrix can only be computed is there's exactly 4 known
+    points.  Obviously, in the real world we want more known
+    points and find a way to get a better estimate.
+    """
+    m = mega_video_metadata.get_view_perspective_matrix()
+    expt = np.array([
+        [200, 100, 0],
+        [100, 100, 0],
+        [0, 0, 1]
+    ])
+    np.testing.assert_array_almost_equal(m, expt)
+
+
+def test_get_view_perspective_matrix_without_enough_data(broken_video_metadata: VideoMetadata) -> None:
+    m = broken_video_metadata.get_view_perspective_matrix()
+    assert m is None