### Question:
CheckExpressionTypeValidator implements ConstraintValidator<CheckExpressionType, ClientExpressionContainer>, ValidationErrorDescriptorBuilder { @Override public void initialize(CheckExpressionType constraintAnnotation) { acceptedExpressions = new HashSet<Class>(Arrays.asList(constraintAnnotation.value())); }  @Override void initialize(CheckExpressionType constraintAnnotation); @Override boolean isValid(ClientExpressionContainer value, ConstraintValidatorContext context); @Override ErrorDescriptor build(ConstraintViolation violation);  }### Answer:
@Test public void initialize_value_success() { CheckExpressionType checkExpressionContainer = mock(CheckExpressionType.class); when(checkExpressionContainer.value()).thenReturn(new Class[]{}); checkExpressionTypeValidator.initialize(checkExpressionContainer); verify(checkExpressionContainer, atLeastOnce()).value(); }