How to use the pgcli.main.PGCli function in pgcli

def test_port_db_uri(tmpdir):
    with mock.patch.object(PGCli, "connect") as mock_connect:
        cli = PGCli(pgclirc_file=str(tmpdir.join("rcfile")))
        cli.connect_uri("postgres://bar:foo@baz.com:2543/testdb")
    mock_connect.assert_called_with(
        database="testdb", host="baz.com", user="bar", passwd="foo", port="2543"
    )

def pgspecial():
    return PGCli().pgspecial

def test_multihost_db_uri(tmpdir):
    with mock.patch.object(PGCli, "connect") as mock_connect:
        cli = PGCli(pgclirc_file=str(tmpdir.join("rcfile")))
        cli.connect_uri(
            "postgres://bar:foo@baz1.com:2543,baz2.com:2543,baz3.com:2543/testdb"
        )
    mock_connect.assert_called_with(
        database="testdb",
        host="baz1.com,baz2.com,baz3.com",
        user="bar",
        passwd="foo",
        port="2543,2543,2543",
    )

def test_missing_rc_dir(tmpdir):
    rcfile = str(tmpdir.join("subdir").join("rcfile"))

    PGCli(pgclirc_file=rcfile)
    assert os.path.exists(rcfile)

def test_i_works(tmpdir, executor):
    sqlfile = tmpdir.join("test.sql")
    sqlfile.write("SELECT NOW()")
    rcfile = str(tmpdir.join("rcfile"))
    cli = PGCli(pgexecute=executor, pgclirc_file=rcfile)
    statement = r"\i {0}".format(sqlfile)
    run(executor, statement, pgspecial=cli.pgspecial)

def test_row_limit_on_non_select(over_limit):
    cli = PGCli()
    stmt = "UPDATE students SET name='Boby'"
    result = cli._should_limit_output(stmt, over_limit)
    assert result is False

    cli = PGCli(row_limit=0)
    result = cli._should_limit_output(stmt, over_limit)
    assert result is False

def test_quoted_db_uri(tmpdir):
    with mock.patch.object(PGCli, "connect") as mock_connect:
        cli = PGCli(pgclirc_file=str(tmpdir.join("rcfile")))
        cli.connect_uri("postgres://bar%5E:%5Dfoo@baz.com/testdb%5B")
    mock_connect.assert_called_with(
        database="testdb[", host="baz.com", user="bar^", passwd="]foo"
    )

def test_row_limit_with_LIMIT_clause(LIMIT, over_limit):
    cli = PGCli(row_limit=LIMIT)
    stmt = "SELECT * FROM students LIMIT 1000"

    result = cli._should_limit_output(stmt, over_limit)
    assert result is False

    cli = PGCli(row_limit=0)
    result = cli._should_limit_output(stmt, over_limit)
    assert result is False

def pset_pager_mocks():
    cli = PGCli()
    cli.watch_command = None
    with mock.patch("pgcli.main.click.echo") as mock_echo, mock.patch(
        "pgcli.main.click.echo_via_pager"
    ) as mock_echo_via_pager, mock.patch.object(cli, "prompt_app") as mock_app:

        yield cli, mock_echo, mock_echo_via_pager, mock_app

if list_dsn:
        try:
            cfg = load_config(pgclirc, config_full_path)
            for alias in cfg["alias_dsn"]:
                click.secho(alias + " : " + cfg["alias_dsn"][alias])
            sys.exit(0)
        except Exception as err:
            click.secho(
                "Invalid DSNs found in the config file. "
                'Please check the "[alias_dsn]" section in pgclirc.',
                err=True,
                fg="red",
            )
            exit(1)

    pgcli = PGCli(
        prompt_passwd,
        never_prompt,
        pgclirc_file=pgclirc,
        row_limit=row_limit,
        single_connection=single_connection,
        less_chatty=less_chatty,
        prompt=prompt,
        prompt_dsn=prompt_dsn,
        auto_vertical_output=auto_vertical_output,
        warn=warn,
    )

    # Choose which ever one has a valid value.
    if dbname_opt and dbname:
        # work as psql: when database is given as option and argument use the argument as user
        username = dbname