### Question:
HttpClientImpl implements OktaHttpClient { @Override public String getHeader(String header) { if (mUrlConnection != null) { return mUrlConnection.getHeaderField(header); } return null; }  @Override InputStream connect(@NonNull Uri uri, @NonNull ConnectionParameters params); @Override void cleanUp(); @Override void cancel(); @Override Map<String, List<String>> getHeaderFields(); @Override String getHeader(String header); @Override int getResponseCode(); @Override int getContentLength(); @Override String getResponseMessage(); @VisibleForTesting HttpURLConnection getUrlConnection();  }### Answer:
@Test public void getHeader() throws Exception { mEndPoint.enqueueUserInfoSuccess(); mHttpClient.connect(Uri.parse(mEndPoint.getUrl()), mRequest.mConnParams); assertNotNull(mHttpClient.getHeader("Content-Length")); }