def freeze(h, output_yaml, resolve, groups):
    """Output installed packages."""
    if not groups:
        groups = filter(lambda group: not group.lower().startswith("bower"),
                        h.requirements.keys())
    else:
        groups = [text_type.strip(group) for group in groups.split(",")]

    if output_yaml:
        for requirements in h.requirements.values():
            for requirement in requirements:
                if resolve and not requirement.version:
                    requirement.load_installed_version()
        click.echo(h.requirements.yaml)
    else:
        for group in groups:
            if not h.requirements[group]:
                continue
            click.echo("# {}".format(group))
            for requirement in h.requirements[group]:
                if resolve and not requirement.version:
                    requirement.load_installed_version()
                click.echo(str(requirement))
def test_ccode_boolean():
    assert ccode(x & y) == "x && y"
    assert ccode(x | y) == "x || y"
    assert ccode(~x) == "!x"
    assert ccode(x & y & z) == "x && y && z"
    assert ccode(x | y | z) == "x || y || z"
    assert ccode((x & y) | z) == "z || x && y"
    assert ccode((x | y) & z) == "z && (x || y)"