### Question:
RequestProviderService { public String getContentTypeHeader() { return getHeader(HttpHeaders.CONTENT_TYPE); }  Optional<Boolean> resolveTppRedirectPreferred(); RequestData getRequestData(); PsuIdData getPsuIdData(); @NotNull UUID getInternalRequestId(); @Nullable String getInstanceId(); String getInternalRequestIdString(); UUID getRequestId(); String getRequestIdString(); boolean isRequestFromPsu(); boolean isRequestFromTPP(); String getPsuIpAddress(); String getTppRedirectURI(); String getTppNokRedirectURI(); String getOAuth2Token(); String getTppRolesAllowedHeader(); @NotNull String getAcceptHeader(); String getContentTypeHeader(); String getEncodedTppQwacCert(); String getTppBrandLoggingInformationHeader(); Boolean getTppRejectionNoFundsPreferred();  }### Answer:
@Test void getContentTypeHeader() { when(httpServletRequest.getHeader(CONTENT_TYPE_HEADER)).thenReturn(CONTENT_TYPE_VALUE); String contentTypeHeader = requestProviderService.getContentTypeHeader(); assertEquals(CONTENT_TYPE_VALUE, contentTypeHeader); }