PreyeaRegmi

class FetchLoanDetail extends UseCase<LoanParamRequest, LoanDetailResponse> {
  final ILoanRepository _loanRepository;

  FetchLoanDetail(this._loanRepository);

  @override
  Stream<LoanDetailResponse> buildUseCase(LoanParamRequest param) {
    return _loanRepository
        .getLoanFromServer(param.amount, param.time)
        .asStream()

PreyeaRegmi

test(
      "Fetch loan should not fail with any exception when mocked with success response",
      () {
    FetchLoanDetail fetchLoanUseCase =
        FetchLoanDetail(MockedSucessRateFetchRepository(LoanDetailDTO(3)));

    fetchLoanUseCase.execute(LoanParamRequest(100, 2), (data) {

    }, expectAsync1((error) {
      expect(error, isNot(isInstanceOf<UseCaseNotImplementedException>()),

PreyeaRegmi

class MockedSucessRateFetchRepository extends ILoanRepository {

  final LoanDetailDTO _mockedResponse;

  MockedSucessRateFetchRepository(this._mockedResponse);

  Future<LoanDetailDTO> getLoanFromServer(double amount, double time) {
    return Future.value(this._mockedResponse);
  }
}

PreyeaRegmi

class LoanParamRequest {
  final double amount, time;

  LoanParamRequest(this.amount, this.time);
}

class LoanDetailResponse {
    String? _emi;
}

PreyeaRegmi

class EMICalculator {

  final double amount, rate, time;
  EMICalculator(this.amount, this.rate, this.time);

  double calculateEMI()
  {
    return amount*rate*(1 + rate)*time/((1+rate)*time-1);
  }
}

PreyeaRegmi

void main()
{
  test("EMI cannot be zero",()
  {
    EMICalculator emiCalculator=EMICalculator(1,2,3);
    //Performing assertion
    expect(emiCalculator.calculateEMI(),greaterThan(0),reason:"EMI calculated is zero");
  });
}

PreyeaRegmi

//Domain Entity responsible for calculating EMI for given params.
class EMICalculator {

  final double amount, rate, time;
  EMICalculator(this.amount, this.rate, this.time);

  double calculateEMI()
  {
    return -1;
  }

PreyeaRegmi

void main()
{

  test("Amount cannot be null",()
  {
    EMICalculator emiCalculator=EMICalculator(1,2,3);
    //Performing assertion
    expect(emiCalculator.amount,isNot(null), reason:"Amount cannot be null");
  });

PreyeaRegmi

//Domain Entity responsible for calculating EMI for given params.
class EMICalculator {  
  final double amount, rate, time;
  EMICalculator(this.amount, this.rate, this.time);  
}

PreyeaRegmi

void main()
{

  test("Amount cannot be null",()
  {
    EMICalculator emiCalculator=EMICalculator();
    //Performing assertion
    expect(emiCalculator.amount,isNot(null), reason:"Amount cannot be null");
  });