rework plugin loading

tests/unit/test_file_checker.py

@@ -1,26 +1,33 @@
 """Unit tests for the FileChecker class."""
+import argparse
 from unittest import mock
 
 import pytest
 
 import flake8
 from flake8 import checker
+from flake8._compat import importlib_metadata
+from flake8.plugins import finder
 
 
 @mock.patch("flake8.checker.FileChecker._make_processor", return_value=None)
 def test_repr(*args):
     """Verify we generate a correct repr."""
     file_checker = checker.FileChecker(
-        "example.py",
-        checks={},
-        options=object(),
+        filename="example.py",
+        plugins=finder.Checkers([], [], []),
+        options=argparse.Namespace(),
     )
     assert repr(file_checker) == "FileChecker for example.py"
 
 
 def test_nonexistent_file():
     """Verify that checking non-existent file results in an error."""
-    c = checker.FileChecker("foobar.py", checks={}, options=object())
+    c = checker.FileChecker(
+        filename="example.py",
+        plugins=finder.Checkers([], [], []),
+        options=argparse.Namespace(),
+    )
 
     assert c.processor is None
     assert not c.should_process
@@ -31,17 +38,21 @@ def test_nonexistent_file():
 
 def test_raises_exception_on_failed_plugin(tmp_path, default_options):
     """Checks that a failing plugin results in PluginExecutionFailed."""
-    foobar = tmp_path / "foobar.py"
-    foobar.write_text("I exist!")  # Create temp file
-    plugin = {
-        "name": "failure",
-        "plugin_name": "failure",  # Both are necessary
-        "parameters": dict(),
-        "plugin": mock.MagicMock(side_effect=ValueError),
-    }
-    """Verify a failing plugin results in an plugin error"""
+    fname = tmp_path.joinpath("t.py")
+    fname.touch()
+    plugin = finder.LoadedPlugin(
+        finder.Plugin(
+            "plugin-name",
+            "1.2.3",
+            importlib_metadata.EntryPoint("X", "dne:dne", "flake8.extension"),
+        ),
+        mock.Mock(side_effect=ValueError),
+        {},
+    )
     fchecker = checker.FileChecker(
-        str(foobar), checks=[], options=default_options
+        filename=str(fname),
+        plugins=finder.Checkers([], [], []),
+        options=default_options,
     )
     with pytest.raises(flake8.exceptions.PluginExecutionFailed):
         fchecker.run_check(plugin)