test(context): add coverage for WorkContext

- Add dedicated unit tests for setup(), package_build_info(),
enable_parallel_builds(), wheels_build, pip_wheel_server_args,
uv_clean_cache(), write_to_graph_to_file(), and clean_build_dirs() in context.py.
- Decompose shared setup into _make_context() and _all_setup_dirs().
- Increase unit test coverage of context.py from 67% to 94%.

Closes #1075

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

Co-authored-by: Cursor

Author: mnadzam

tests/test_context.py

@@ -1,30 +1,220 @@
 import os
 import pathlib
+from unittest.mock import Mock, patch
+
+import pytest
+from packaging.requirements import Requirement
 
 from fromager import context
 
 
-def test_pip_constraints_args(tmp_path: pathlib.Path) -> None:
-    constraints_file = tmp_path / "constraints.txt"
-    constraints_file.write_text("\n")  # the file has to exist
-    ctx = context.WorkContext(
+def _make_context(
+    tmp_path: pathlib.Path,
+    constraints_file: str | None = None,
+    wheel_server_url: str = "",
+    cleanup: bool = True,
+) -> context.WorkContext:
+    return context.WorkContext(
         active_settings=None,
-        constraints_file=str(constraints_file),
+        constraints_file=constraints_file,
         patches_dir=tmp_path / "overrides/patches",
         sdists_repo=tmp_path / "sdists-repo",
         wheels_repo=tmp_path / "wheels-repo",
         work_dir=tmp_path / "work-dir",
+        wheel_server_url=wheel_server_url,
+        cleanup=cleanup,
     )
+
+
+def _all_setup_dirs(ctx: context.WorkContext) -> list[pathlib.Path]:
+    return [
+        ctx.work_dir,
+        ctx.sdists_repo,
+        ctx.sdists_downloads,
+        ctx.sdists_builds,
+        ctx.wheels_repo,
+        ctx.wheels_downloads,
+        ctx.wheels_prebuilt,
+        ctx.wheels_build,
+        ctx.uv_cache,
+        ctx.logs_dir,
+    ]
+
+
+def test_pip_constraints_args(tmp_path: pathlib.Path) -> None:
+    constraints_file = tmp_path / "constraints.txt"
+    constraints_file.write_text("\n")  # the file has to exist
+    ctx = _make_context(tmp_path, constraints_file=str(constraints_file))
     ctx.setup()
     assert ["--constraint", os.fspath(constraints_file)] == ctx.pip_constraint_args
 
-    ctx = context.WorkContext(
-        active_settings=None,
-        constraints_file=None,
-        patches_dir=tmp_path / "overrides/patches",
-        sdists_repo=tmp_path / "sdists-repo",
-        wheels_repo=tmp_path / "wheels-repo",
-        work_dir=tmp_path / "work-dir",
-    )
+    ctx = _make_context(tmp_path)
     ctx.setup()
     assert [] == ctx.pip_constraint_args
+
+
+def test_setup_creates_directories(tmp_path: pathlib.Path) -> None:
+    ctx = _make_context(tmp_path)
+    ctx.setup()
+
+    for d in _all_setup_dirs(ctx):
+        assert d.is_dir(), f"{d} was not created"
+
+
+def test_setup_is_idempotent(tmp_path: pathlib.Path) -> None:
+    ctx = _make_context(tmp_path)
+    ctx.setup()
+
+    test_file = ctx.logs_dir / "test_file.txt"
+    test_file.write_text("test text")
+
+    ctx.setup()
+
+    for d in _all_setup_dirs(ctx):
+        assert d.is_dir(), f"{d} was not created"
+    assert test_file.read_text() == "test text"
+
+
+def test_package_build_info_extracts_name_from_requirement(
+    tmp_context: context.WorkContext,
+) -> None:
+    to_return = Mock()
+    with patch.object(
+        tmp_context.settings, "package_build_info", return_value=to_return
+    ) as mock_pbi:
+        result = tmp_context.package_build_info(Requirement("numpy>=1.0"))
+
+    mock_pbi.assert_called_once_with("numpy")
+    assert result is to_return
+
+
+def test_package_build_info_passes_string_directly(
+    tmp_context: context.WorkContext,
+) -> None:
+    to_return = Mock()
+    with patch.object(
+        tmp_context.settings, "package_build_info", return_value=to_return
+    ) as mock_pbi:
+        result = tmp_context.package_build_info("numpy")
+
+    mock_pbi.assert_called_once_with("numpy")
+    assert result is to_return
+
+
+def test_wheels_build_default(tmp_context: context.WorkContext) -> None:
+    assert tmp_context.wheels_build == tmp_context.wheels_build_base
+
+
+def test_wheels_build_parallel(tmp_context: context.WorkContext) -> None:
+    tmp_context.enable_parallel_builds()
+
+    result = tmp_context.wheels_build
+
+    assert result.parent == tmp_context.wheels_build_base
+    assert result.is_dir()
+
+
+def test_write_to_graph_to_file(tmp_path: pathlib.Path) -> None:
+    ctx = _make_context(tmp_path)
+    ctx.setup()
+
+    with patch.object(ctx.dependency_graph, "serialize") as mock_serialize:
+        ctx.write_to_graph_to_file()
+
+    mock_serialize.assert_called_once()
+    assert ctx.graph_file.exists()
+
+
+def test_pip_wheel_server_args_https(tmp_path: pathlib.Path) -> None:
+    ctx = _make_context(tmp_path, wheel_server_url="https://wheels.example.com/simple")
+    assert ctx.pip_wheel_server_args == [
+        "--index-url",
+        "https://wheels.example.com/simple",
+    ]
+
+
+def test_pip_wheel_server_args_http(tmp_path: pathlib.Path) -> None:
+    ctx = _make_context(tmp_path, wheel_server_url="http://wheels.example.com/simple")
+    assert ctx.pip_wheel_server_args == [
+        "--index-url",
+        "http://wheels.example.com/simple",
+        "--trusted-host",
+        "wheels.example.com",
+    ]
+
+
+def test_uv_clean_cache_no_args_raises(tmp_path: pathlib.Path) -> None:
+    ctx = _make_context(tmp_path)
+    ctx.setup()
+
+    with pytest.raises(ValueError):
+        ctx.uv_clean_cache()
+
+
+@patch("fromager.context.external_commands.run")
+def test_uv_clean_cache_calls_run(mock_run: Mock, tmp_path: pathlib.Path) -> None:
+    ctx = _make_context(tmp_path)
+    ctx.setup()
+
+    ctx.uv_clean_cache(Requirement("numpy"), Requirement("torch"))
+
+    mock_run.assert_called_once()
+    cmd = mock_run.call_args[0][0]
+    assert cmd == ["uv", "clean", "cache", "numpy", "torch"]
+    extra_env = mock_run.call_args[1]["extra_environ"]
+    assert extra_env["UV_CACHE_DIR"] == str(ctx.uv_cache)
+
+
+def test_clean_build_dirs_raises_when_env_is_child_of_sdist(
+    tmp_path: pathlib.Path,
+) -> None:
+    ctx = _make_context(tmp_path)
+    ctx.setup()
+
+    sdist_root = tmp_path / "source"
+    sdist_root.mkdir()
+    build_env = Mock()
+    build_env.path = sdist_root / "venv"
+    build_env.path.mkdir()
+
+    with pytest.raises(ValueError):
+        ctx.clean_build_dirs(sdist_root_dir=sdist_root, build_env=build_env)
+
+    assert sdist_root.is_dir()
+    assert build_env.path.is_dir()
+
+
+def test_clean_build_dirs_removes_dirs_when_cleanup_enabled(
+    tmp_path: pathlib.Path,
+) -> None:
+    ctx = _make_context(tmp_path, cleanup=True)
+    ctx.setup()
+
+    sdist_root = tmp_path / "source"
+    sdist_root.mkdir()
+    build_env = Mock()
+    build_env.path = tmp_path / "build-env"
+    build_env.path.mkdir()
+
+    ctx.clean_build_dirs(sdist_root_dir=sdist_root, build_env=build_env)
+
+    assert not sdist_root.exists()
+    assert not build_env.path.exists()
+
+
+def test_clean_build_dirs_keeps_dirs_when_cleanup_disabled(
+    tmp_path: pathlib.Path,
+) -> None:
+    ctx = _make_context(tmp_path, cleanup=False)
+    ctx.setup()
+
+    sdist_root = tmp_path / "source"
+    sdist_root.mkdir()
+    build_env = Mock()
+    build_env.path = tmp_path / "build-env"
+    build_env.path.mkdir()
+
+    ctx.clean_build_dirs(sdist_root_dir=sdist_root, build_env=build_env)
+
+    assert sdist_root.exists()
+    assert build_env.path.exists()