Code review comment: are you adding tests where the null values are actual values?

Code under review:
public void runAllClientFunctionsWithResponseAsync(HttpClient httpClient) {
        String groupId = getGroupId("runAllClientFunctionsWithResponseAsync");
        CallingServerClientBuilder builder = getCallingServerClientUsingConnectionString(httpClient);
        CallingServerAsyncClient callingServerAsyncClient =
            setupAsyncClient(builder, "runAllClientFunctionsWithResponseAsync");
        String recordingId = "";
        List<CallConnectionAsync> callConnections = new ArrayList<>();
        ServerCallAsync serverCallAsync = null;

        try {
            callConnections = createAsyncCall(callingServerAsyncClient, groupId, fromUser, toUser, CALLBACK_URI);
            serverCallAsync = callingServerAsyncClient.initializeServerCall(groupId);

            Response<StartCallRecordingResult> startRecordingResponse =
                serverCallAsync.startRecordingWithResponse(CALLBACK_URI, null, null, null, null).block();
            assert startRecordingResponse != null;
            assertEquals(startRecordingResponse.getStatusCode(), 200);
            StartCallRecordingResult startCallRecordingResult = startRecordingResponse.getValue();
            recordingId = startCallRecordingResult.getRecordingId();
            validateCallRecordingStateWithResponse(serverCallAsync, recordingId, CallRecordingState.ACTIVE);

            Response<Void> pauseResponse = serverCallAsync.pauseRecordingWithResponse(recordingId).block();
            assert pauseResponse != null;
            assertEquals(pauseResponse.getStatusCode(), 200);
            validateCallRecordingStateWithResponse(serverCallAsync, recordingId, CallRecordingState.INACTIVE);

            Response<Void> resumeResponse = serverCallAsync.resumeRecordingWithResponse(recordingId).block();
            assert resumeResponse != null;
            assertEquals(resumeResponse.getStatusCode(), 200);
            validateCallRecordingStateWithResponse(serverCallAsync, recordingId, CallRecordingState.ACTIVE);
        } catch (Exception e) {
            System.out.println("Error: " + e.getMessage());
            throw e;
        } finally {
            if (serverCallAsync != null) {
                try {
                    Response<Void> stopResponse = serverCallAsync.stopRecordingWithResponse(recordingId).block();
                    assert stopResponse != null;
                    assertEquals(stopResponse.getStatusCode(), 200);
                } catch (Exception e) {
                    System.out.println("Error stopping recording: " + e.getMessage());
                }
            }

            cleanUpConnectionsAsync(callConnections);
        }
    }

Line commented on: serverCallAsync.startRecordingWithResponse(CALLBACK_URI, null, null, null, null).block();

Revised code:
public void runAllClientFunctionsWithResponseAsync(HttpClient httpClient) {
        String groupId = getGroupId("runAllClientFunctionsWithResponseAsync");
        CallingServerClientBuilder builder = getCallingServerClientUsingConnectionString(httpClient);
        CallingServerAsyncClient callingServerAsyncClient =
            setupAsyncClient(builder, "runAllClientFunctionsWithResponseAsync");
        String recordingId = "";
        List<CallConnectionAsync> callConnections = new ArrayList<>();
        ServerCallAsync serverCallAsync = null;

        try {
            callConnections = createAsyncCall(callingServerAsyncClient, groupId, fromUser, toUser, CALLBACK_URI);
            serverCallAsync = callingServerAsyncClient.initializeServerCall(groupId);

            Response<StartCallRecordingResult> startRecordingResponse =
                serverCallAsync.startRecordingWithResponse(CALLBACK_URI, null, null).block();
            assert startRecordingResponse != null;
            assertEquals(startRecordingResponse.getStatusCode(), 200);
            StartCallRecordingResult startCallRecordingResult = startRecordingResponse.getValue();
            recordingId = startCallRecordingResult.getRecordingId();
            validateCallRecordingStateWithResponse(serverCallAsync, recordingId, CallRecordingState.ACTIVE);

            Response<Void> pauseResponse = serverCallAsync.pauseRecordingWithResponse(recordingId).block();
            assert pauseResponse != null;
            assertEquals(pauseResponse.getStatusCode(), 200);
            validateCallRecordingStateWithResponse(serverCallAsync, recordingId, CallRecordingState.INACTIVE);

            Response<Void> resumeResponse = serverCallAsync.resumeRecordingWithResponse(recordingId).block();
            assert resumeResponse != null;
            assertEquals(resumeResponse.getStatusCode(), 200);
            validateCallRecordingStateWithResponse(serverCallAsync, recordingId, CallRecordingState.ACTIVE);
        } catch (Exception e) {
            System.out.println("Error: " + e.getMessage());
            throw e;
        } finally {
            if (serverCallAsync != null) {
                try {
                    Response<Void> stopResponse = serverCallAsync.stopRecordingWithResponse(recordingId).block();
                    assert stopResponse != null;
                    assertEquals(stopResponse.getStatusCode(), 200);
                } catch (Exception e) {
                    System.out.println("Error stopping recording: " + e.getMessage());
                }
            }

            cleanUpConnectionsAsync(callConnections);
        }
    }