1 files changed, 131 insertions, 0 deletions
diff --git a/tests/unit/metadata/test_metadata.py b/tests/unit/metadata/test_metadata.py
new file mode 100644
index 000000000..f77178fb9
--- /dev/null
+++ b/tests/unit/metadata/test_metadata.py
@@ -0,0 +1,131 @@
+import logging
+import os
+from pathlib import Path
+from typing import cast
+from unittest import mock
+
+import pytest
+from pip._vendor.packaging.utils import NormalizedName
+
+from pip._internal.metadata import (
+    BaseDistribution,
+    get_directory_distribution,
+    get_environment,
+    get_wheel_distribution,
+)
+from pip._internal.metadata.base import FilesystemWheel
+from pip._internal.models.direct_url import DIRECT_URL_METADATA_NAME, ArchiveInfo
+from tests.lib.wheel import make_wheel
+
+
+@mock.patch.object(BaseDistribution, "read_text", side_effect=FileNotFoundError)
+def test_dist_get_direct_url_no_metadata(mock_read_text: mock.Mock) -> None:
+    class FakeDistribution(BaseDistribution):
+        pass
+
+    dist = FakeDistribution()
+    assert dist.direct_url is None
+    mock_read_text.assert_called_once_with(DIRECT_URL_METADATA_NAME)
+
+
+@mock.patch.object(BaseDistribution, "read_text", return_value="{}")
+def test_dist_get_direct_url_invalid_json(
+    mock_read_text: mock.Mock, caplog: pytest.LogCaptureFixture
+) -> None:
+    class FakeDistribution(BaseDistribution):
+        canonical_name = cast(NormalizedName, "whatever")  # Needed for error logging.
+
+    dist = FakeDistribution()
+    with caplog.at_level(logging.WARNING):
+        assert dist.direct_url is None
+
+    mock_read_text.assert_called_once_with(DIRECT_URL_METADATA_NAME)
+    assert (
+        caplog.records[-1]
+        .getMessage()
+        .startswith(
+            "Error parsing direct_url.json for whatever:",
+        )
+    )
+
+
+def test_metadata_reads_egg_info_requires_txt(tmp_path: Path) -> None:
+    """Check Requires-Dist is obtained from requires.txt if absent in PKG-INFO."""
+    egg_info_path = tmp_path / "whatever.egg-info"
+    egg_info_path.mkdir()
+    dist = get_directory_distribution(str(egg_info_path))
+    assert dist.installed_with_setuptools_egg_info
+    pkg_info_path = egg_info_path / "PKG-INFO"
+    pkg_info_path.write_text("Name: whatever\n")
+    egg_info_path.joinpath("requires.txt").write_text("pkga\npkgb\n")
+    assert dist.metadata.get_all("Requires-Dist") == ["pkga", "pkgb"]
+
+
+def test_metadata_pkg_info_requires_priority(tmp_path: Path) -> None:
+    """Check Requires-Dist in PKG-INFO has priority over requires.txt."""
+    egg_info_path = tmp_path / "whatever.egg-info"
+    egg_info_path.mkdir()
+    dist = get_directory_distribution(str(egg_info_path))
+    assert dist.installed_with_setuptools_egg_info
+    pkg_info_path = egg_info_path / "PKG-INFO"
+    pkg_info_path.write_text(
+        "Name: whatever\nRequires-Dist: pkgc\nRequires-Dist: pkgd\n"
+    )
+    egg_info_path.joinpath("requires.txt").write_text("pkga\npkgb\n")
+    assert dist.metadata.get_all("Requires-Dist") == ["pkgc", "pkgd"]
+
+
+@mock.patch.object(
+    BaseDistribution,
+    "read_text",
+    return_value='{"url": "https://e.c/p.tgz", "archive_info": {}}',
+)
+def test_dist_get_direct_url_valid_metadata(mock_read_text: mock.Mock) -> None:
+    class FakeDistribution(BaseDistribution):
+        pass
+
+    dist = FakeDistribution()
+    direct_url = dist.direct_url
+    assert direct_url is not None
+    mock_read_text.assert_called_once_with(DIRECT_URL_METADATA_NAME)
+    assert direct_url.url == "https://e.c/p.tgz"
+    assert isinstance(direct_url.info, ArchiveInfo)
+
+
+def test_metadata_dict(tmp_path: Path) -> None:
+    """Basic test of BaseDistribution metadata_dict.
+
+    More tests are available in the original pkg_metadata project where this
+    function comes from, and which we may vendor in the future.
+    """
+    wheel_path = make_wheel(name="pkga", version="1.0.1").save_to_dir(tmp_path)
+    wheel = FilesystemWheel(wheel_path)
+    dist = get_wheel_distribution(wheel, "pkga")
+    metadata_dict = dist.metadata_dict
+    assert metadata_dict["name"] == "pkga"
+    assert metadata_dict["version"] == "1.0.1"
+
+
+def test_no_dist_found_in_wheel(tmp_path: Path) -> None:
+    location = os.fspath(tmp_path.joinpath("pkg-1-py3-none-any.whl"))
+    make_wheel(name="pkg", version="1").save_to(location)
+    assert get_environment([location]).get_distribution("pkg") is None
+
+
+def test_dist_found_in_directory_named_whl(tmp_path: Path) -> None:
+    dir_path = tmp_path.joinpath("pkg-1-py3-none-any.whl")
+    info_path = dir_path.joinpath("pkg-1.dist-info")
+    info_path.mkdir(parents=True)
+    info_path.joinpath("METADATA").write_text("Name: pkg")
+    location = os.fspath(dir_path)
+    dist = get_environment([location]).get_distribution("pkg")
+    assert dist is not None and dist.location is not None
+    assert Path(dist.location) == Path(location)
+
+
+def test_dist_found_in_zip(tmp_path: Path) -> None:
+    location = os.fspath(tmp_path.joinpath("pkg.zip"))
+    make_wheel(name="pkg", version="1").save_to(location)
+    dist = get_environment([location]).get_distribution("pkg")
+    assert dist is not None and dist.location is not None
+    assert Path(dist.location) == Path(location)