test(hooks): add coverage for hook plugin system

Closes #1033

Signed-off-by: Marcel Nadzam <mnadzam@redhat.com>

Co-Authored-By: Cursor

Author: mnadzam

tests/test_hooks.py

@@ -0,0 +1,216 @@
+from __future__ import annotations
+
+import pathlib
+import typing
+from importlib.metadata import EntryPoint
+from unittest.mock import MagicMock, Mock, patch
+
+import pytest
+from packaging.requirements import Requirement
+
+from fromager import hooks
+
+
+@pytest.fixture(autouse=True)
+def _clear_hook_cache() -> typing.Generator[None, None, None]:
+    hooks._mgrs.clear()
+    yield
+    hooks._mgrs.clear()
+
+
+def _make_fake_ext(plugin: typing.Callable[..., typing.Any]) -> Mock:
+    ext = Mock()
+    ext.plugin = plugin
+    return ext
+
+
+def test_die_on_plugin_load_failure_raises() -> None:
+    ep = EntryPoint(name="bad_plugin", value="some.module:func", group="fromager.hooks")
+    original_err = ImportError("no such module")
+
+    with pytest.raises(RuntimeError, match="bad_plugin") as exc_info:
+        hooks._die_on_plugin_load_failure(
+            mgr=Mock(),
+            ep=ep,
+            err=original_err,
+        )
+
+    assert exc_info.value.__cause__ is original_err
+
+
+@patch("fromager.hooks.hook.HookManager")
+def test_get_hooks_creates_manager(mock_hm_cls: Mock) -> None:
+    fake_mgr = MagicMock()
+    fake_mgr.names.return_value = ["my_hook"]
+    mock_hm_cls.return_value = fake_mgr
+
+    result = hooks._get_hooks("post_build")
+
+    mock_hm_cls.assert_called_once_with(
+        namespace="fromager.hooks",
+        name="post_build",
+        invoke_on_load=False,
+        on_load_failure_callback=hooks._die_on_plugin_load_failure,
+    )
+    assert result is fake_mgr
+
+
+@patch("fromager.hooks.hook.HookManager")
+def test_get_hooks_returns_cached(mock_hm_cls: Mock) -> None:
+    fake_mgr = MagicMock()
+    fake_mgr.names.return_value = ["my_hook"]
+    mock_hm_cls.return_value = fake_mgr
+
+    first = hooks._get_hooks("post_build")
+    second = hooks._get_hooks("post_build")
+
+    mock_hm_cls.assert_called_once()
+    assert first is second
+
+
+@patch("fromager.hooks._get_hooks")
+def test_run_post_build_hooks_exception_propagates(mock_get: Mock) -> None:
+
+    def bad_plugin(**kwargs: typing.Any) -> None:
+        raise ValueError("hook failed")
+
+    fake_mgr = MagicMock()
+    fake_mgr.names.return_value = ["bad"]
+    fake_mgr.__iter__ = Mock(return_value=iter([_make_fake_ext(bad_plugin)]))
+    mock_get.return_value = fake_mgr
+
+    with pytest.raises(ValueError, match="hook failed"):
+        hooks.run_post_build_hooks(
+            ctx=Mock(),
+            req=Requirement("pkg"),
+            dist_name="pkg",
+            dist_version="1.0",
+            sdist_filename=pathlib.Path("/tmp/a.tar.gz"),
+            wheel_filename=pathlib.Path("/tmp/a.whl"),
+        )
+
+
+@patch("fromager.hooks._get_hooks")
+def test_run_post_build_hooks_calls_plugin(mock_get: Mock) -> None:
+    called_with: dict[str, typing.Any] = {}
+
+    def fake_plugin(**kwargs: typing.Any) -> None:
+        called_with.update(kwargs)
+
+    fake_mgr = MagicMock()
+    fake_mgr.names.return_value = ["my_hook"]
+    fake_mgr.__iter__ = Mock(return_value=iter([_make_fake_ext(fake_plugin)]))
+    mock_get.return_value = fake_mgr
+
+    ctx = Mock()
+    req = Requirement("numpy>=1.0")
+    sdist = pathlib.Path("/tmp/numpy-1.0.tar.gz")
+    wheel = pathlib.Path("/tmp/numpy-1.0-cp312-linux_x86_64.whl")
+
+    hooks.run_post_build_hooks(
+        ctx=ctx,
+        req=req,
+        dist_name="numpy",
+        dist_version="1.0",
+        sdist_filename=sdist,
+        wheel_filename=wheel,
+    )
+
+    assert called_with["ctx"] is ctx
+    assert called_with["req"] is req
+    assert called_with["dist_name"] == "numpy"
+    assert called_with["dist_version"] == "1.0"
+    assert called_with["sdist_filename"] is sdist
+    assert called_with["wheel_filename"] is wheel
+
+
+@patch("fromager.hooks._get_hooks")
+def test_run_post_bootstrap_hooks_calls_plugin(mock_get: Mock) -> None:
+    called_with: dict[str, typing.Any] = {}
+
+    def fake_plugin(**kwargs: typing.Any) -> None:
+        called_with.update(kwargs)
+
+    fake_mgr = MagicMock()
+    fake_mgr.names.return_value = ["my_hook"]
+    fake_mgr.__iter__ = Mock(return_value=iter([_make_fake_ext(fake_plugin)]))
+    mock_get.return_value = fake_mgr
+
+    ctx = Mock()
+    req = Requirement("flask>=2.0")
+
+    hooks.run_post_bootstrap_hooks(
+        ctx=ctx,
+        req=req,
+        dist_name="flask",
+        dist_version="2.0",
+        sdist_filename=None,
+        wheel_filename=None,
+    )
+
+    assert called_with["ctx"] is ctx
+    assert called_with["req"] is req
+    assert called_with["dist_name"] == "flask"
+    assert called_with["dist_version"] == "2.0"
+    assert called_with["sdist_filename"] is None
+    assert called_with["wheel_filename"] is None
+
+
+@patch("fromager.hooks._get_hooks")
+def test_run_prebuilt_wheel_hooks_calls_plugin(mock_get: Mock) -> None:
+    called_with: dict[str, typing.Any] = {}
+
+    def fake_plugin(**kwargs: typing.Any) -> None:
+        called_with.update(kwargs)
+
+    fake_mgr = MagicMock()
+    fake_mgr.names.return_value = ["my_hook"]
+    fake_mgr.__iter__ = Mock(return_value=iter([_make_fake_ext(fake_plugin)]))
+    mock_get.return_value = fake_mgr
+
+    ctx = Mock()
+    req = Requirement("torch>=2.0")
+    wheel = pathlib.Path("/tmp/torch-2.0-cp312-linux_x86_64.whl")
+
+    hooks.run_prebuilt_wheel_hooks(
+        ctx=ctx,
+        req=req,
+        dist_name="torch",
+        dist_version="2.0",
+        wheel_filename=wheel,
+    )
+
+    assert called_with["ctx"] is ctx
+    assert called_with["req"] is req
+    assert called_with["dist_name"] == "torch"
+    assert called_with["dist_version"] == "2.0"
+    assert called_with["wheel_filename"] is wheel
+    assert "sdist_filename" not in called_with
+
+
+@patch("fromager.hooks.overrides._get_dist_info", return_value=("mypkg", "1.0.0"))
+@patch("fromager.hooks.extension.ExtensionManager")
+def test_log_hooks_logs_each_extension(
+    mock_em_cls: Mock,
+    mock_dist_info: Mock,
+) -> None:
+    ext_a = Mock()
+    ext_a.name = "post_build"
+    ext_a.module_name = "my_plugins.hooks"
+
+    ext_b = Mock()
+    ext_b.name = "post_bootstrap"
+    ext_b.module_name = "other_plugins.hooks"
+
+    mock_em_cls.return_value = [ext_a, ext_b]
+
+    hooks.log_hooks()
+
+    mock_em_cls.assert_called_once_with(
+        namespace="fromager.hooks",
+        invoke_on_load=False,
+        on_load_failure_callback=hooks._die_on_plugin_load_failure,
+    )
+    assert mock_dist_info.call_count == 2
+    mock_dist_info.assert_any_call("my_plugins.hooks")
+    mock_dist_info.assert_any_call("other_plugins.hooks")