EmailAddressPartsExtractorTest.java

public class EmailAddressPartsExtractorTest {
    private EmailAddressPartsExtractor extractor = new EmailAddressPartsExtractor();

    @Test
    public void extractUsername() {
        assertThat(extractor.extractUsername("elnur.blog@example.com"), is("elnur.blog"));
    }

    @Test
    public void extractHost() {
        assertThat(extractor.extractHostname("elnur.blog@example.com"), is("example.com"));
    }

    @Test(expected = InvalidEmailAddressException.class)
    public void failToExtractUsernameFromAddressWithoutAtCharacter() {
        extractor.extractUsername("elnur.example.com");
    }

    @Test(expected = InvalidEmailAddressException.class)
    public void failToExtractUsernameFromInvalidAddressWithMoreThanOneAtCharacter() {
        extractor.extractUsername("elnur@example@com");
    }

    @Test(expected = InvalidEmailAddressException.class)
    public void failToExtractHostnameFromAddressWithoutAtCharacter() {
        extractor.extractHostname("elnur.example.com");
    }

    @Test(expected = InvalidEmailAddressException.class)
    public void failToExtractHostnameFromInvalidAddressWithMoreThanOneAtCharacter() {
        extractor.extractHostname("elnur@example@com");
    }
}