Add tests for folder reading and > 1 MTL files (#11)

Test reading from a folder and check if an exception is raised when
multiple MTL files are present.

xlandsat/tests/__init__.py

@@ -0,0 +1,3 @@
+# Copyright (c) 2022 The xlandsat developers.
+# Distributed under the terms of the MIT License.
+# SPDX-License-Identifier: MIT

xlandsat/tests/test_read.py

@@ -4,16 +4,67 @@
 """
 Test the main IO functionality
 """
+import pathlib
+import shutil
+import tempfile
+
 import pooch
+import pytest
 
 from .._read import load_scene
 
 
-def test_load_scene_minimal():
-    "Minimal check that things don't crash."
+def test_load_scene_archive():
+    "Check basic things about loading a scene from a tar archive"
     path = pooch.retrieve(
         "doi:10.6084/m9.figshare.21665630.v1/cropped-after.tar.gz",
         known_hash="md5:4ae61a2d7a8b853c727c0c433680cece",
     )
     scene = load_scene(path)
     assert scene.attrs["title"] == "Landsat 8 scene from 2019-01-30 (path/row=218/74)"
+    assert set(scene.data_vars) == set(
+        ["red", "green", "blue", "nir", "swir1", "swir2"]
+    )
+    assert scene.red.shape == (300, 400)
+
+
+def test_load_scene_folder():
+    "Check basic things about loading a scene from a folder"
+    paths = pooch.retrieve(
+        "doi:10.6084/m9.figshare.21665630.v1/cropped-after.tar.gz",
+        known_hash="md5:4ae61a2d7a8b853c727c0c433680cece",
+        processor=pooch.Untar(),
+    )
+    # Unpack the archive and get the folder name
+    path = pathlib.Path(paths[0]).parent
+    assert path.is_dir()
+    scene = load_scene(path)
+    assert scene.attrs["title"] == "Landsat 8 scene from 2019-01-30 (path/row=218/74)"
+    assert set(scene.data_vars) == set(
+        ["red", "green", "blue", "nir", "swir1", "swir2"]
+    )
+    assert scene.red.shape == (300, 400)
+
+
+def test_load_scene_fail_multiple_mtl_files():
+    "Check that loading fails when there are multiple MTL.txt files"
+    paths = pooch.retrieve(
+        "doi:10.6084/m9.figshare.21665630.v1/cropped-after.tar.gz",
+        known_hash="md5:4ae61a2d7a8b853c727c0c433680cece",
+        processor=pooch.Untar(),
+    )
+    # Unpack the archive and get the folder name
+    path = pathlib.Path(paths[0]).parent
+    assert path.is_dir()
+    # Find the name of the MTL file
+    mtl = list(path.glob("*_MTL.txt"))
+    assert len(mtl) == 1
+    mtl = mtl[0].name
+    # Duplicate the scene into a temporary folder and add an extra file
+    with tempfile.TemporaryDirectory() as tmpdir:
+        duplicate = pathlib.Path(tmpdir) / "duplicate_scene"
+        shutil.copytree(path, duplicate)
+        shutil.copy(pathlib.Path(path) / mtl, duplicate / ("copy_" + mtl))
+        with pytest.raises(ValueError) as error:
+            load_scene(duplicate)
+        assert "Found 2" in str(error)