PreyeaRegmi

import java.util.*
import kotlin.math.pow

/**
 * @author Preyea R. Regmi
 * Entry point to the division operation
 * 1) Takes input from CLI as string and parse into decimal format.
 * 2) Converts the input and divisor into binary string
 * 3) Performs division on binary representation
 * 4) Prints Quotient and Remainder in both binary and decimal format

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 LoanDetailResponse {
    final String _emi;

  LoanDetailResponse(this._emi);

   static from(EMICalculator emiCalculator) {
     return LoanDetailResponse(emiCalculator.calculateEMI().toString());
  }
}

PreyeaRegmi

test(
      "EMI must be 150391.64490861617 for amount = 10,000, rate = 15%, time =24 months",
      () {
    FetchLoanDetail fetchLoanUseCase =
        FetchLoanDetail(MockedSucessRateFetchRepository(LoanDetailDTO("15")));

    fetchLoanUseCase.execute(
        LoanParamRequest(10000, 24), expectAsync1((data) {
      expect("150391.64490861617",equals( data._emi),reason: "Emi calculation invalid");

PreyeaRegmi

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

  final double amount, rate, time;
  EMICalculator(this.amount, this.rate, this.time){
    if(amount<0)
      throw ArgumentError("Amount cannot be less than zero");
    if(rate<0)
      throw ArgumentError("Rate cannot be less than zero");
    if(time<0)

PreyeaRegmi

test(
      "Use case must also fail when fetch loan fails from network",
          () {
        FetchLoanDetail fetchLoanUseCase =
        FetchLoanDetail(MockedFailedRateFetchRepository(RateFetchFailType.NETWORK));

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

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

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;
}