If the body of the lambda passed to assertThrows contains multiple statements, execution of the lambda will stop at the first statement that throws an exception and all subsequent statements will be ignored.

This means that:

• Any set-up logic in the lambda will cause the test to incorrectly pass if it throws the expected exception.
• Any assertions that run after the statement that throws will never be executed.

Don't do this:

assertThrows(
    UnsupportedOperationException.class,
    () -> {
        AppendOnlyList list = new AppendOnlyList();
        list.add(0, "a");
        list.remove(0);
        assertThat(list).containsExactly("a");
    });

Do this instead:

AppendOnlyList list = new AppendOnlyList();
list.add(0, "a");
assertThrows(
    UnsupportedOperationException.class,
    () -> list.remove(0));
assertThat(list).containsExactly("a");