@Test
 public void emptyString_ReturnsFalse() {
   assertFalse(TextChecker.checkIfEmailProper(""));
 }
 @Test
 public void invalidEmailNoUsername_ReturnsFalse() {
   assertFalse(TextChecker.checkIfEmailProper("@email.com"));
 }
 @Test
 public void invalidEmailDoubleDot_ReturnsFalse() {
   assertFalse(TextChecker.checkIfEmailProper("*****@*****.**"));
 }
 @Test
 public void invalidEmailNoTld_ReturnsFalse() {
   assertFalse(TextChecker.checkIfEmailProper("name@email"));
 }
 @Test
 public void correctEmailSubDomain_ReturnsTrue() {
   assertTrue(TextChecker.checkIfEmailProper("*****@*****.**"));
 }
 @Test
 public void correctEmailSimple_ReturnsTrue() {
   assertTrue(TextChecker.checkIfEmailProper("*****@*****.**"));
 }