def test_greet_three_visitors_one_shouting():
    assert GreetingMessageGenerator().greet_visitor(
        "Amy", "BRIAN",
        "Charlotte") == "Hello, Amy and Charlotte. AND HELLO BRIAN!"
def test_greet_visitor_none_as_input():
    assert GreetingMessageGenerator().greet_visitor(
        None) == "Hello, my friend."
def test_greet_two_visitors_first_one_empty():
    assert GreetingMessageGenerator().greet_visitor(
        "", "Jane") == "Hello, my friend and Jane."
def test_greet_three_visitors():
    assert GreetingMessageGenerator().greet_visitor(
        "Amy", "Brian", "Charlotte") == "Hello, Amy, Brian, and Charlotte."
def test_greet_two_visitors_second_one_none():
    assert GreetingMessageGenerator().greet_visitor(
        "Jill", None) == "Hello, Jill and my friend."
def test_greet_visitor_simple_hello_positive_case():
    assert GreetingMessageGenerator().greet_visitor("Bob") == "Hello, Bob."
def test_greet_two_visitors():
    assert GreetingMessageGenerator().greet_visitor(
        "Jill", "Jane") == "Hello, Jill and Jane."
def test_greet_visitor_shouting():
    assert GreetingMessageGenerator().greet_visitor("BOB") == "HELLO BOB!"
def test_greet_visitor_empty_name_as_input():
    assert GreetingMessageGenerator().greet_visitor("") == "Hello, my friend."