@Test
void joining() {

    assertNotNull(Expressions.joining(
        ToString.of(string -> (String) string),
        ToString.of(string -> (String) string)));
    assertNotNull(Expressions.joining(
        " ",
        ToString.of(string -> (String) string),
        ToString.of(string -> (String) string)));
    assertNotNull(Expressions.joining(
        " ",
        "prefix",
        "suffix",
        ToString.of(string -> (String) string),
        ToString.of(string -> (String) string)));
    assertNotNull(Expressions.joining(
        ToString.of(string -> (String) string),
        ToString.of(string -> (String) string),
        ToString.of(string -> (String) string)));
    assertNotNull(Expressions.joining(
        " ",
        ToString.of(string -> (String) string),
        ToString.of(string -> (String) string),
        ToString.of(string -> (String) string)));
    assertNotNull(Expressions.joining(
        " ",
        "prefix",
        "suffix",
        ToString.of(string -> (String) string),
        ToString.of(string -> (String) string),
        ToString.of(string -> (String) string)));
}