Add unit tests for samplers

tests/samplers/test_samplers.py

@@ -0,0 +1,58 @@
+from typing import Iterator
+
+import pytest
+
+from torchgeo.datasets import BoundingBox
+from torchgeo.samplers import GeoSampler, GridGeoSampler, RandomGeoSampler
+
+
+class CustomGeoSampler(GeoSampler):
+    def __init__(self) -> None:
+        pass
+
+    def __iter__(self) -> Iterator[BoundingBox]:
+        for i in range(len(self)):
+            yield BoundingBox(i, i, i, i, i, i)
+
+    def __len__(self) -> int:
+        return 2
+
+
+class TestGeoSampler:
+    @pytest.fixture(scope="function")
+    def sampler(self) -> GeoSampler:
+        return CustomGeoSampler()
+
+    def test_iter(self, sampler: GeoSampler) -> None:
+        assert next(iter(sampler)) == BoundingBox(0, 0, 0, 0, 0, 0)
+
+    def test_len(self, sampler: GeoSampler) -> None:
+        assert len(sampler) == 2
+
+    def test_abstract(self) -> None:
+        with pytest.raises(TypeError, match="Can't instantiate abstract class"):
+            GeoSampler(None)  # type: ignore[abstract]
+
+
+class TestRandomGeoSampler:
+    @pytest.fixture(scope="function")
+    def sampler(self) -> GeoSampler:
+        roi = BoundingBox(0, 10, 20, 30, 40, 50)
+        return RandomGeoSampler(roi, size=5, length=10)
+
+    def test_iter(self, sampler: GeoSampler) -> None:
+        query = next(iter(sampler))
+
+        assert sampler.roi.minx <= query.minx <= sampler.roi.maxx
+        assert sampler.roi.minx <= query.maxx <= sampler.roi.maxx
+        assert sampler.roi.miny <= query.miny <= sampler.roi.maxy
+        assert sampler.roi.miny <= query.maxy <= sampler.roi.maxy
+        assert sampler.roi.mint <= query.mint <= sampler.roi.maxt
+        assert sampler.roi.mint <= query.maxt <= sampler.roi.maxt
+
+        assert query.maxx - query.minx == sampler.size
+        assert query.maxy - query.miny == sampler.size
+        assert query.maxt - query.mint == sampler.roi.maxt - sampler.roi.mint
+
+    def test_len(self, sampler: GeoSampler) -> None:
+        assert len(sampler) == sampler.length