@Test
void language() {

    assertThat(message.language("messages_en_US.properties")).isEqualTo("en_US");
    assertThat(message.language("messages_en.properties")).isEqualTo("en");
    assertThat(message.language("messages.properties")).isEqualTo(MessageImpl.DEFAULT_LANGUAGE);
    assertThatThrownBy(() -> message.language("invalid.message_E.properties"))
            .isInstanceOf(Error.class)
            .hasMessageContaining("property path must match 'path/name_language.properties' pattern");
}