1 files changed, 123 insertions, 0 deletions
diff --git a/tests/unit/metadata/test_metadata_pkg_resources.py b/tests/unit/metadata/test_metadata_pkg_resources.py
new file mode 100644
index 000000000..ab1a56107
--- /dev/null
+++ b/tests/unit/metadata/test_metadata_pkg_resources.py
@@ -0,0 +1,123 @@
+import email.message
+import itertools
+from typing import List, cast
+from unittest import mock
+
+import pytest
+from pip._vendor.packaging.specifiers import SpecifierSet
+from pip._vendor.packaging.version import parse as parse_version
+
+from pip._internal.exceptions import UnsupportedWheel
+from pip._internal.metadata.pkg_resources import (
+    Distribution,
+    Environment,
+    InMemoryMetadata,
+)
+
+pkg_resources = pytest.importorskip("pip._vendor.pkg_resources")
+
+
+def _dist_is_local(dist: mock.Mock) -> bool:
+    return dist.kind != "global" and dist.kind != "user"
+
+
+def _dist_in_usersite(dist: mock.Mock) -> bool:
+    return dist.kind == "user"
+
+
+@pytest.fixture(autouse=True)
+def patch_distribution_lookups(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setattr(Distribution, "local", property(_dist_is_local))
+    monkeypatch.setattr(Distribution, "in_usersite", property(_dist_in_usersite))
+
+
+class _MockWorkingSet(List[mock.Mock]):
+    def require(self, name: str) -> None:
+        pass
+
+
+workingset = _MockWorkingSet(
+    (
+        mock.Mock(test_name="global", project_name="global"),
+        mock.Mock(test_name="editable", project_name="editable"),
+        mock.Mock(test_name="normal", project_name="normal"),
+        mock.Mock(test_name="user", project_name="user"),
+    )
+)
+
+workingset_stdlib = _MockWorkingSet(
+    (
+        mock.Mock(test_name="normal", project_name="argparse"),
+        mock.Mock(test_name="normal", project_name="wsgiref"),
+    )
+)
+
+
+@pytest.mark.parametrize(
+    "ws, req_name",
+    itertools.chain(
+        itertools.product(
+            [workingset],
+            (d.project_name for d in workingset),
+        ),
+        itertools.product(
+            [workingset_stdlib],
+            (d.project_name for d in workingset_stdlib),
+        ),
+    ),
+)
+def test_get_distribution(ws: _MockWorkingSet, req_name: str) -> None:
+    """Ensure get_distribution() finds all kinds of distributions."""
+    dist = Environment(ws).get_distribution(req_name)
+    assert dist is not None
+    assert cast(Distribution, dist)._dist.project_name == req_name
+
+
+def test_get_distribution_nonexist() -> None:
+    dist = Environment(workingset).get_distribution("non-exist")
+    assert dist is None
+
+
+def test_wheel_metadata_works() -> None:
+    name = "simple"
+    version = "0.1.0"
+    require_a = "a==1.0"
+    require_b = 'b==1.1; extra == "also_b"'
+    requires = [require_a, require_b, 'c==1.2; extra == "also_c"']
+    extras = ["also_b", "also_c"]
+    requires_python = ">=3"
+
+    metadata = email.message.Message()
+    metadata["Name"] = name
+    metadata["Version"] = version
+    for require in requires:
+        metadata["Requires-Dist"] = require
+    for extra in extras:
+        metadata["Provides-Extra"] = extra
+    metadata["Requires-Python"] = requires_python
+
+    dist = Distribution(
+        pkg_resources.DistInfoDistribution(
+            location="<in-memory>",
+            metadata=InMemoryMetadata({"METADATA": metadata.as_bytes()}, "<in-memory>"),
+            project_name=name,
+        ),
+    )
+
+    assert name == dist.canonical_name == dist.raw_name
+    assert parse_version(version) == dist.version
+    assert set(extras) == set(dist.iter_provided_extras())
+    assert [require_a] == [str(r) for r in dist.iter_dependencies()]
+    assert [require_a, require_b] == [
+        str(r) for r in dist.iter_dependencies(["also_b"])
+    ]
+    assert metadata.as_string() == dist.metadata.as_string()
+    assert SpecifierSet(requires_python) == dist.requires_python
+
+
+def test_wheel_metadata_throws_on_bad_unicode() -> None:
+    metadata = InMemoryMetadata({"METADATA": b"\xff"}, "<in-memory>")
+
+    with pytest.raises(UnsupportedWheel) as e:
+        metadata.get_metadata("METADATA")
+    assert "METADATA" in str(e.value)