### Question:
CheckParametersExpressionContainerValidator implements ConstraintValidator<CheckParametersExpressionContainer, Map<String, ClientExpressionContainer>>, ValidationErrorDescriptorBuilder { @Override public void initialize(CheckParametersExpressionContainer constraintAnnotation) { acceptedExpressions = new HashSet<Class>(Arrays.asList(constraintAnnotation.value())); }  @Override void initialize(CheckParametersExpressionContainer constraintAnnotation); @Override boolean isValid(Map<String, ClientExpressionContainer> expressionMap, ConstraintValidatorContext context); @Override ErrorDescriptor build(ConstraintViolation violation);  }### Answer:
@Test public void initialize_success() { CheckParametersExpressionContainer checkParametersExpressionContainer = mock(CheckParametersExpressionContainer.class); when(checkParametersExpressionContainer.value()).thenReturn(new Class[]{}); checkParametersExpressionContainerValidator.initialize(checkParametersExpressionContainer); verify(checkParametersExpressionContainer, atLeastOnce()).value(); }