Clean variant command tests up

Use a dedicated test package instead of reusing the plugin package,
as suggested by Jonathan Dekhtiar.  Put a fixed `/dev/null` plugin path
in metadata to avoid checksum mismatches (and make updating artifacts
easier), and mock the plugin loader instead.

Author: mgorny

tests/artifacts/test-package/pyproject.toml

@@ -0,0 +1,9 @@
+[build-system]
+requires = ["flit_core >=3.11,<4"]
+build-backend = "flit_core.buildapi"
+
+[project]
+name = "test-package"
+version = "0"
+description = "Installable package for testing"
+requires-python = ">=3.9"

tests/artifacts/test-package/test_package.py

@@ -5,32 +5,28 @@
 from variantlib.commands.main import main
 
 if TYPE_CHECKING:
-    from pathlib import Path
-
     import pytest
 
 
 def test_analyze_wheel_regular(
     caplog: pytest.LogCaptureFixture,
     capsys: pytest.CaptureFixture[str],
     mocked_entry_points: None,
-    test_plugin_package_wheel_path: Path,
 ) -> None:
-    main(["analyze-wheel", "-i", str(test_plugin_package_wheel_path)])
+    main(["analyze-wheel", "-i", "tests/artifacts/test_package-0-py3-none-any.whl"])
     assert capsys.readouterr().out == ""
     assert "Standard Wheel" in caplog.text
 
 
 def test_analyze_wheel_null_variant(
     capsys: pytest.CaptureFixture[str],
     mocked_entry_points: None,
-    test_plugin_package_wheel_path: Path,
 ) -> None:
     main(
         [
             "analyze-wheel",
             "-i",
-            "tests/artifacts/test_plugin_package-0-py3-none-any-00000000.whl",
+            "tests/artifacts/test_package-0-py3-none-any-00000000.whl",
         ]
     )
     assert (
@@ -45,13 +41,12 @@ def test_analyze_wheel_null_variant(
 def test_analyze_wheel_variant(
     capsys: pytest.CaptureFixture[str],
     mocked_entry_points: None,
-    test_plugin_package_wheel_path: Path,
 ) -> None:
     main(
         [
             "analyze-wheel",
             "-i",
-            "tests/artifacts/test_plugin_package-0-py3-none-any-5d8be4b9.whl",
+            "tests/artifacts/test_package-0-py3-none-any-5d8be4b9.whl",
         ]
     )
     assert (

tests/artifacts/test_package-0-py3-none-any-00000000.whl

@@ -11,19 +11,16 @@ def test_generate_index_json(
     tmp_path: Path,
 ) -> None:
     filenames = [
-        "test_plugin_package-0-py3-none-any.whl",
-        "test_plugin_package-0-py3-none-any-00000000.whl",
-        "test_plugin_package-0-py3-none-any-5d8be4b9.whl",
-        "test_plugin_package-0-py3-none-any-ac31c899.whl",
+        "test_package-0-py3-none-any.whl",
+        "test_package-0-py3-none-any-00000000.whl",
+        "test_package-0-py3-none-any-5d8be4b9.whl",
     ]
     artifact_dir = Path("tests/artifacts")
     for filename in filenames:
         copy(artifact_dir / filename, tmp_path / filename)
 
     main(["generate-index-json", "-d", str(tmp_path)])
-    assert json.loads(
-        (tmp_path / "test_plugin_package-0-variants.json").read_text()
-    ) == {
+    assert json.loads((tmp_path / "test_package-0-variants.json").read_text()) == {
         "$schema": "https://variants-schema.wheelnext.dev/",
         "default-priorities": {
             "feature": {},
@@ -35,10 +32,7 @@ def test_generate_index_json(
         "providers": {
             "installable_plugin": {
                 "plugin-api": "test_plugin_package",
-                "requires": [
-                    "test-plugin-package @ "
-                    "file://{plugin_path}/test_plugin_package-0-py3-none-any.whl",
-                ],
+                "requires": ["test-plugin-package @ file:///dev/null"],
             },
         },
         "variants": {
@@ -49,10 +43,5 @@ def test_generate_index_json(
                     "feat2": "val2b",
                 },
             },
-            "ac31c899": {
-                "foo": {
-                    "bar": "baz",
-                },
-            },
         },
     }