Add tests for LandCoverAI Dataset

tests/datasets/test_landcoverai.py

@@ -0,0 +1,65 @@
+import os
+from pathlib import Path
+import shutil
+from typing import Generator
+
+from _pytest.fixtures import SubRequest
+import pytest
+from pytest import MonkeyPatch
+import torch
+from torch.utils.data import ConcatDataset
+import torchvision.datasets.utils
+
+from torchgeo.datasets import LandCoverAI
+from torchgeo.transforms import Identity
+
+
+def download_url(url: str, root: str, *args: str) -> None:
+    shutil.copy(url, root)
+
+
+class TestLandCoverAI:
+    @pytest.fixture(params=["train", "val", "test"])
+    def dataset(
+        self,
+        monkeypatch: Generator[MonkeyPatch, None, None],
+        tmp_path: Path,
+        request: SubRequest,
+    ) -> LandCoverAI:
+        monkeypatch.setattr(  # type: ignore[attr-defined]
+            torchvision.datasets.utils, "download_url", download_url
+        )
+        md5 = "8a84857267619c8cf22730193b3b1ada"
+        monkeypatch.setattr(LandCoverAI, "md5", md5)  # type: ignore[attr-defined]
+        url = os.path.join("tests", "data", "landcoverai", "landcover.ai.v1.zip")
+        monkeypatch.setattr(LandCoverAI, "url", url)  # type: ignore[attr-defined]
+        (tmp_path / "landcoverai").mkdir()
+        root = str(tmp_path)
+        split = request.param
+        transforms = Identity()
+        return LandCoverAI(root, split, transforms, download=True, checksum=True)
+
+    def test_getitem(self, dataset: LandCoverAI) -> None:
+        x = dataset[0]
+        assert isinstance(x, dict)
+        assert isinstance(x["image"], torch.Tensor)
+        assert isinstance(x["mask"], torch.Tensor)
+
+    def test_len(self, dataset: LandCoverAI) -> None:
+        assert len(dataset) == 2
+
+    def test_add(self, dataset: LandCoverAI) -> None:
+        ds = dataset + dataset
+        assert isinstance(ds, ConcatDataset)
+        assert len(ds) == 4
+
+    def test_already_downloaded(self, dataset: LandCoverAI) -> None:
+        LandCoverAI(root=dataset.root, download=True)
+
+    def test_invalid_split(self) -> None:
+        with pytest.raises(AssertionError):
+            LandCoverAI(split="foo")
+
+    def test_not_downloaded(self, tmp_path: Path) -> None:
+        with pytest.raises(RuntimeError, match="Dataset not found or corrupted."):
+            LandCoverAI(str(tmp_path))