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mechanical-refactor-verify

Make mechanical refactoring (file splits, function moves, module extractions, renames) machine-checkable instead of eyeballed. Reproduce a relocation commit byte-for-byte from faithful primitives, and split an extraction into a verifiable prepare + move + postpare. Use when doing or reviewing such changes.

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scripts/tests/reproduction_utils/test_add_imports.py

scripts/tests/reproduction_utils/test_add_imports.pyBrowse 41 files
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import subprocessimport sysfrom pathlib import Path import pytest sys.path.insert(0, str(Path(__file__).resolve().parents[2])) import mechanical_refactor_reproduction_utils as rrfrom mechanical_refactor_reproduction_utils import (    Repro,    _def_span,    _find_class,    _find_def,    _replace_span,    _slice_span,    dedent,    exec_command,    git_add_and_commit,    verify_mechanical_refactor,)from reproduction_testlib import _apply, _commit, _git, _write  # noqa: F401 # --- add_import ----------------------------------------------------------------  def test_add_import_appends_after_last_top_level_import(tmp_path: Path) -> None:    """A new import is inserted right after the last module-level import."""    (tmp_path / "m.py").write_text("import os\nimport sys\n\nx = 1\n")    r = Repro("b", "t").add_import("m.py", "from pkg import Thing")    _apply(r, tmp_path)    assert (        tmp_path / "m.py"    ).read_text() == "import os\nimport sys\nfrom pkg import Thing\n\nx = 1\n"  # --- add_imported_name ---------------------------------------------------------  def test_add_imported_name_extends_a_single_line_import(tmp_path: Path) -> None:    """A new name is appended to an existing from-import on the same statement."""    (tmp_path / "m.py").write_text("from pkg import a\n\nx = 1\n")    r = Repro("b", "t").add_imported_name("m.py", module="pkg", name="b")    _apply(r, tmp_path)    assert (tmp_path / "m.py").read_text() == "from pkg import a, b\n\nx = 1\n"  def test_add_imported_name_carries_an_asname(tmp_path: Path) -> None:    """The added name keeps its `as` alias."""    (tmp_path / "m.py").write_text("from pkg import a\n")    r = Repro("b", "t").add_imported_name("m.py", module="pkg", name="b", asname="c")    _apply(r, tmp_path)    assert (tmp_path / "m.py").read_text() == "from pkg import a, b as c\n"  def test_add_imported_name_refuses_a_commented_import(tmp_path: Path) -> None:    """An import carrying comments is refused, since a rebuild would drop them."""    (tmp_path / "m.py").write_text("from pkg import (\n    a,  # keep\n)\n")    r = Repro("b", "t").add_imported_name("m.py", module="pkg", name="b")    with pytest.raises(AssertionError):        _apply(r, tmp_path)  def test_add_imported_name_rejects_a_name_already_present(tmp_path: Path) -> None:    """Adding a name the import already has fails loudly."""    (tmp_path / "m.py").write_text("from pkg import a, b\n")    r = Repro("b", "t").add_imported_name("m.py", module="pkg", name="b")    with pytest.raises(AssertionError):        _apply(r, tmp_path)  def test_add_imported_name_raises_without_a_matching_import(tmp_path: Path) -> None:    """A file lacking a `from module import` for the module fails loudly."""    (tmp_path / "m.py").write_text("from other import a\n")    r = Repro("b", "t").add_imported_name("m.py", module="pkg", name="b")    with pytest.raises(AssertionError):        _apply(r, tmp_path)  # --- repath_import / add_typechecking_import -----------------------------------  def test_add_typechecking_import_inserts_in_block(tmp_path: Path) -> None:    """The import is appended inside the existing TYPE_CHECKING block."""    (tmp_path / "m.py").write_text(        "from typing import TYPE_CHECKING\n"        "\n"        "if TYPE_CHECKING:\n"        "    from a import X\n"        "\n"        "\n"        "def f():\n"        "    pass\n"    )    r = Repro("b", "t").add_typechecking_import("m.py", "from b import Y")    _apply(r, tmp_path)    assert (tmp_path / "m.py").read_text() == (        "from typing import TYPE_CHECKING\n"        "\n"        "if TYPE_CHECKING:\n"        "    from a import X\n"        "    from b import Y\n"        "\n"        "\n"        "def f():\n"        "    pass\n"    )  def test_add_typechecking_import_creates_missing_block(tmp_path: Path) -> None:    """With no TYPE_CHECKING block, one is created after the trailing module import."""    (tmp_path / "m.py").write_text(        "from typing import TYPE_CHECKING\n\nfrom a import X\n\n\ndef f():\n    pass\n"    )    r = Repro("b", "t").add_typechecking_import("m.py", "from b import Y")    _apply(r, tmp_path)    assert (tmp_path / "m.py").read_text() == (        "from typing import TYPE_CHECKING\n"        "\n"        "from a import X\n"        "\n"        "if TYPE_CHECKING:\n"        "    from b import Y\n"        "\n"        "\n"        "def f():\n"        "    pass\n"    )  def test_add_import_into_an_empty_file(tmp_path: Path) -> None:    """Adding an import to an empty file writes just the statement."""    (tmp_path / "m.py").write_text("")    r = Repro("b", "t").add_import("m.py", "import os")    _apply(r, tmp_path)    assert (tmp_path / "m.py").read_text() == "import os\n"  def test_add_import_lands_below_a_module_docstring(tmp_path: Path) -> None:    """In a file with only a docstring, the new import must land below the docstring."""    (tmp_path / "m.py").write_text('"""Module doc."""\n\nx = 1\n')    r = Repro("b", "t").add_import("m.py", "import os")    _apply(r, tmp_path)    assert (tmp_path / "m.py").read_text().startswith('"""Module doc."""')  def test_add_typechecking_import_matches_qualified_typing_form(tmp_path: Path) -> None:    """A `if typing.TYPE_CHECKING:` block is recognized and receives the import."""    (tmp_path / "m.py").write_text(        "import typing\n"        "\n"        "if typing.TYPE_CHECKING:\n"        "    from a import X\n"        "\n"        "\n"        "def f():\n"        "    pass\n"    )    r = Repro("b", "t").add_typechecking_import("m.py", "from b import Y")    _apply(r, tmp_path)    assert (tmp_path / "m.py").read_text() == (        "import typing\n"        "\n"        "if typing.TYPE_CHECKING:\n"        "    from a import X\n"        "    from b import Y\n"        "\n"        "\n"        "def f():\n"        "    pass\n"    )  def test_add_typechecking_import_after_a_multiline_final_import(tmp_path: Path) -> None:    """The insert lands after the closing paren of a multi-line final guarded import."""    (tmp_path / "m.py").write_text(        "from typing import TYPE_CHECKING\n"        "\n"        "if TYPE_CHECKING:\n"        "    from a import (\n"        "        X,\n"        "    )\n"        "\n"        "x = 1\n"    )    r = Repro("b", "t").add_typechecking_import("m.py", "from b import Y")    _apply(r, tmp_path)    assert (tmp_path / "m.py").read_text() == (        "from typing import TYPE_CHECKING\n"        "\n"        "if TYPE_CHECKING:\n"        "    from a import (\n"        "        X,\n"        "    )\n"        "    from b import Y\n"        "\n"        "x = 1\n"    )  def test_add_typechecking_import_raises_without_imports(tmp_path: Path) -> None:    """A file with no imports cannot anchor a new TYPE_CHECKING block and fails loudly."""    (tmp_path / "m.py").write_text("x = 1\n")    r = Repro("b", "t").add_typechecking_import("m.py", "from b import Y")    with pytest.raises(AssertionError):        _apply(r, tmp_path)  def test_add_typechecking_import_drops_a_lone_pass_placeholder(tmp_path: Path) -> None:    """Populating a `pass`-only TYPE_CHECKING block replaces the placeholder."""    (tmp_path / "m.py").write_text(        "from typing import TYPE_CHECKING\n\nif TYPE_CHECKING:\n    pass\n\nx = 1\n"    )    r = Repro("b", "t").add_typechecking_import("m.py", "from b import Y")    _apply(r, tmp_path)    assert (tmp_path / "m.py").read_text() == (        "from typing import TYPE_CHECKING\n"        "\n"        "if TYPE_CHECKING:\n"        "    from b import Y\n"        "\n"        "x = 1\n"    )  def test_add_typechecking_import_keeps_a_pass_that_is_not_alone(tmp_path: Path) -> None:    """A `pass` beside a real import is left untouched; only the new import is appended."""    (tmp_path / "m.py").write_text(        "from typing import TYPE_CHECKING\n"        "\n"        "if TYPE_CHECKING:\n"        "    from a import X\n"        "    pass\n"        "\n"        "x = 1\n"    )    r = Repro("b", "t").add_typechecking_import("m.py", "from b import Y")    _apply(r, tmp_path)    assert (tmp_path / "m.py").read_text() == (        "from typing import TYPE_CHECKING\n"        "\n"        "if TYPE_CHECKING:\n"        "    from a import X\n"        "    pass\n"        "    from b import Y\n"        "\n"        "x = 1\n"    )  # --- add_import(after=...) -----------------------------------------------------  def test_add_import_after_anchors_into_a_split_import_block(tmp_path: Path) -> None:    """With `after`, the import lands right after the named import -- needed when a    statement splits the imports into separate blocks and the default (after the last    import) would land in the wrong block."""    (tmp_path / "m.py").write_text(        "import os\n\n_flag = os.getpid()\n\nfrom pkg import a\n\nx = 1\n"    )    r = Repro("b", "t").add_import("m.py", "from new import Thing", after="import os")    _apply(r, tmp_path)    assert (tmp_path / "m.py").read_text() == (        "import os\nfrom new import Thing\n\n_flag = os.getpid()\n\nfrom pkg import a\n\nx = 1\n"    )  def test_add_import_after_raises_when_anchor_absent(tmp_path: Path) -> None:    """An `after` substring that matches no top-level import raises."""    (tmp_path / "m.py").write_text("import os\n\nx = 1\n")    r = Repro("b", "t").add_import("m.py", "from new import Thing", after="import nope")    with pytest.raises(AssertionError):        _apply(r, tmp_path)
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