How to use the testpath.assert_isfile function in testpath

def test_wheel_package(copy_sample):
    td = copy_sample('package1')
    make_wheel_in(td / 'flit.ini', td)
    assert_isfile(td / 'package1-0.1-py2.py3-none-any.whl')

def test_write_license():
    with TemporaryDirectory() as td:
        ib = init.IniterBase(td)
        ib.write_license('mit', 'Thomas Kluyver')
        assert_isfile(Path(td, 'LICENSE'))

def test_compression(tmp_path):
    info = make_wheel_in(samples_dir / 'module1_ini' / 'flit.ini', tmp_path)
    assert_isfile(info.file)
    with zipfile.ZipFile(str(info.file)) as zf:
        for name in [
            'module1.py',
            'module1-0.1.dist-info/METADATA',
        ]:
            assert zf.getinfo(name).compress_type == zipfile.ZIP_DEFLATED

def test_symlink_package(self):
        if os.name == 'nt':
            raise SkipTest("symlink")
        Installer.from_ini_path(samples_dir / 'package1' / 'pyproject.toml', symlink=True).install()
        assert_islink(self.tmpdir / 'site-packages' / 'package1',
                      to=samples_dir / 'package1' / 'package1')
        assert_isfile(self.tmpdir / 'scripts' / 'pkg_script')
        with (self.tmpdir / 'scripts' / 'pkg_script').open() as f:
            assert f.readline().strip() == "#!" + sys.executable
        self._assert_direct_url(
            samples_dir / 'package1', 'package1', '0.1', expected_editable=True
        )

def test_wheel_src_module(copy_sample):
    td = copy_sample('module3')
    make_wheel_in(td / 'flit.ini', td)

    whl_file = td / 'module3-0.1-py2.py3-none-any.whl'
    assert_isfile(whl_file)
    with unpack(whl_file) as unpacked:
        assert_isfile(Path(unpacked, 'module3.py'))
        assert_isdir(Path(unpacked, 'module3-0.1.dist-info'))
        assert_isfile(Path(unpacked, 'module3-0.1.dist-info', 'LICENSE'))

def _assert_direct_url(self, directory, package, version, expected_editable):
        direct_url_file = (
            self.tmpdir
            / 'site-packages'
            / '{}-{}.dist-info'.format(package, version)
            / 'direct_url.json'
        )
        assert_isfile(direct_url_file)
        with direct_url_file.open() as f:
            direct_url = json.load(f)
            assert direct_url['url'].startswith('file:///')
            assert direct_url['url'] == directory.as_uri()
            assert direct_url['dir_info'].get('editable') is expected_editable

def test_tomlify(copy_sample, monkeypatch):
    td = copy_sample('with_flit_ini')
    monkeypatch.chdir(td)

    tomlify.main(argv=[])

    pyproject_toml = (td / 'pyproject.toml')
    assert_isfile(pyproject_toml)

    with pyproject_toml.open(encoding='utf-8') as f:
        content = pytoml.load(f)

    assert 'build-system' in content
    assert 'tool' in content
    assert 'flit' in content['tool']
    flit_table = content['tool']['flit']
    assert 'metadata' in flit_table
    assert 'scripts' in flit_table
    assert 'entrypoints' in flit_table

def test_entry_points(copy_sample):
    td = copy_sample('entrypoints_valid')
    make_wheel_in(td / 'flit.ini', td)
    assert_isfile(td / 'package1-0.1-py2.py3-none-any.whl')
    with unpack(td / 'package1-0.1-py2.py3-none-any.whl') as td_unpack:
        entry_points = Path(td_unpack, 'package1-0.1.dist-info', 'entry_points.txt')
        assert_isfile(entry_points)
        cp = configparser.ConfigParser()
        cp.read(str(entry_points))
        assert 'console_scripts' in cp.sections()
        assert 'myplugins' in cp.sections()

'1'    # License (1 -> MIT)
                ]
    with TemporaryDirectory() as td, \
          patch_data_dir(), \
          faking_input(responses):
        ti = init.TerminalIniter(td)
        ti.initialise()

        generated = Path(td) / 'pyproject.toml'
        assert_isfile(generated)
        with generated.open() as f:
            data = pytoml.load(f)
        assert data['tool']['flit']['metadata'][
                   'author-email'] == "test@example.com"
        license = Path(td) / 'LICENSE'
        assert_isfile(license)
        with license.open() as f:
            license_text = f.read()
        assert license_text.startswith("The MIT License (MIT)")
        assert "{year}" not in license_text
        assert "Test Author" in license_text