error matcher

error_hamcrest.java

private Matcher<ErrorCollector> containsErrorCode(final ErrorCode errorCode) {
        return new BaseMatcher<ErrorCollector>() {
            @Override
            public boolean matches(final Object item) {
                ErrorCollector allErrors = (ErrorCollector) item;
                FieldError fieldError = allErrors.getFieldError(errorCode.getField());
                if (fieldError == null) {
                    return false;
                }
                if (!fieldError.getCode().equals(errorCode.getCode())) {
                    return false;
                }
                if (!fieldError.getDefaultMessage().equals(errorCode.getMessage())) {
                    return false;
                }
                return true;
            }

            @Override
            public void describeMismatch(Object item, Description mismatchDescription) {
                ErrorCollector allErrors = (ErrorCollector) item;
                String errorList = String.join(", ", allErrors.getFieldErrors()
                        .stream()
                        .map(FieldError::getField)
                        .collect(Collectors.toList()));
                mismatchDescription.appendText("Error keys were: ").appendText(errorList);
            }

            @Override
            public void describeTo(final Description description) {
                description.appendText("Errors should include ").appendValue(errorCode);
            }
        };
    }