FabledGrimoire/tests/test_measure_duplication.py

"""The DRY close-out measure.

Stdlib-only and kept in scripts/ so any project can run a scratch copy of it,
so these tests import it by path rather than as a package.

What matters is the after-only list: it is the part of the measure that finds
something a pass could not, so it must name a copy the change CREATED and stay
quiet about one that was already there. A list that repeats old duplication
every time is one nobody reads.
"""
import importlib.util
import pathlib
import shutil
import subprocess

import pytest

_PATH = pathlib.Path(__file__).resolve().parents[1] / "scripts" / "measure_duplication.py"
_spec = importlib.util.spec_from_file_location("measure_duplication", _PATH)
dup = importlib.util.module_from_spec(_spec)
_spec.loader.exec_module(dup)


BODY = """
def load(user_id, note_id):
    # a comment the measure ignores
    if not allowed(user_id, note_id):
        raise ValueError("note {} not found".format(note_id))
    with session() as s:
        row = s.get(Row, note_id)
        if row is None:
            raise ValueError("not a row")
        return row
"""


def _files(**texts):
    return [(name, text.encode()) for name, text in texts.items()]


def test_comments_blanks_and_bare_punctuation_are_not_code():
    lines = dup.significant_lines('x = 1\n\n// note\n# note\n  });\n-- sql note\ny = "two"\n')
    assert [t for _, t in lines] == ["x = 1", 'y = "S"']
    assert [n for n, _ in lines] == [1, 7]


def test_a_preprocessor_line_is_code_and_a_hash_comment_is_not():
    lines = dup.significant_lines("#include <x.h>\n# a comment\n#!/bin/sh\n")
    assert [t for _, t in lines] == ["#include <x.h>"]


def test_copies_that_differ_only_in_their_strings_are_one_copy():
    other = BODY.replace('"not a row"', '"no such row"')
    result = dup.measure(_files(**{"a.py": BODY, "b.py": other}), [], [], window=6)
    py = result["py"]
    assert py["dup_windows"] > 0
    assert py["dup_lines"] == py["lines"]
    assert py["share"] == 1.0


def test_unrelated_files_measure_zero():
    other = "\n".join(f"v{i} = compute({i})" for i in range(20))
    result = dup.measure(_files(**{"a.py": BODY, "b.py": other}), [], [], window=6)
    assert result["py"]["dup_lines"] == 0


def test_the_first_matching_group_claims_a_file():
    groups = [("tests", ["tests/*"]), ("py", ["*.py"])]
    assert dup.group_of("tests/test_x.py", groups) == "tests"
    assert dup.group_of("src/x.py", groups) == "py"
    assert dup.group_of("README.md", groups) is None


def test_without_groups_only_source_extensions_are_measured():
    assert dup.group_of("src/x.go", []) == "go"
    assert dup.group_of("docs/x.md", []) is None
    assert dup.group_of("Makefile", []) is None


def test_excluded_paths_are_not_measured():
    result = dup.measure(
        _files(**{"a.py": BODY, "gen/b.py": BODY}), [], ["gen/*"], window=6,
    )
    assert result["py"]["dup_lines"] == 0


def test_a_copy_the_change_created_is_listed_after_only():
    before = dup.measure(_files(**{"a.py": BODY, "c.py": "z = 1\n"}), [], [], window=6)
    after = dup.measure(_files(**{"a.py": BODY, "c.py": BODY}), [], [], window=6)
    fresh = dup.only_after(before, after)
    assert [e["files"] for e in fresh["py"]] == [["a.py", "c.py"]]
    assert fresh["py"][0]["at"] == ["a.py:2", "c.py:2"]


def test_a_copy_that_was_already_there_is_not_listed():
    both = _files(**{"a.py": BODY, "b.py": BODY})
    before = dup.measure(both, [], [], window=6)
    after = dup.measure(both, [], [], window=6)
    assert dup.only_after(before, after) == {}


def test_the_report_shows_before_and_after_side_by_side():
    before = dup.measure(_files(**{"a.py": BODY}), [], [], window=6)
    after = dup.measure(_files(**{"a.py": BODY, "b.py": BODY}), [], [], window=6)
    text = dup.report(before, after, dup.only_after(before, after), show=5)
    assert "0.0% → 100.0%" in text
    assert "a.py:2, b.py:2" in text


@pytest.mark.skipif(shutil.which("git") is None, reason="needs git")
def test_a_revision_is_read_without_a_checkout(tmp_path, capsys):
    def git(*args):
        subprocess.run(
            ["git", "-C", str(tmp_path), "-c", "user.name=t", "-c", "user.email=t@t", *args],
            check=True, capture_output=True,
        )

    git("init", "-q")
    (tmp_path / "a.py").write_text(BODY)
    git("add", "a.py")
    git("commit", "-qm", "one copy")
    (tmp_path / "b.py").write_text(BODY)
    git("add", "b.py")

    assert dup.main(["--repo", str(tmp_path), "--before", "HEAD"]) == 0
    out = capsys.readouterr().out
    assert "Duplicated only after: 1 file set(s)" in out
    assert "a.py:2, b.py:2" in out