Unit tests added

test/unit_test/viewmodel_test.dart

@@ -0,0 +1,132 @@
+import 'dart:io';
+
+import 'package:easy_cc_flutter/MainViewModel.dart';
+import 'package:easy_cc_flutter/Utils/SelectionType.dart';
+import 'package:easy_cc_flutter/data/model/Currency.dart';
+import 'package:easy_cc_flutter/data/prefs/CurrencyPair.dart';
+import 'package:easy_cc_flutter/data/repository/RepositoryImpl.dart';
+import 'package:easy_cc_flutter/locator.dart';
+import 'package:flutter_dotenv/flutter_dotenv.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:mockito/annotations.dart';
+import 'package:mockito/mockito.dart';
+import 'package:easy_cc_flutter/Utils/ViewState.dart';
+
+import 'viewmodel_test.mocks.dart';
+
+@GenerateMocks([
+  RepositoryImpl
+])
+void main() {
+  late MainViewModel mainViewModel;
+  late RepositoryImpl repository;
+
+  const String fromCurrency = "AUD - Australian Dollar";
+  const String toCurrency = "GBP - British Pound Sterling";
+
+  setUpAll(() async {
+    // Setup
+    await dotenv.load(fileName: "test/resources/test_res.env");
+    // Create mock object.
+    repository = MockRepositoryImpl();
+
+    locator.registerLazySingleton(() => repository);
+
+    mainViewModel = MainViewModel();
+  });
+
+  test('get currency pair from prefs', () {
+    // Given
+    CurrencyPair pair = CurrencyPair(fromCurrency, toCurrency);
+
+    // When
+    when(repository.getConversionPair()).thenReturn(pair);
+
+    // Then
+    String fromSelection = mainViewModel.getConversionPair(SelectionType.conversionFrom);
+    String toSelection = mainViewModel.getConversionPair(SelectionType.conversionTo);
+    expect(fromSelection, fromCurrency);
+    expect(toSelection, toCurrency);
+  });
+
+  test('get currency pair from prefs nothing stored', () {
+    // Given
+    CurrencyPair pair = CurrencyPair(null, null);
+
+    // When
+    when(repository.getConversionPair()).thenReturn(pair);
+
+    // Then
+    String fromSelection = mainViewModel.getConversionPair(SelectionType.conversionFrom);
+    String toSelection = mainViewModel.getConversionPair(SelectionType.conversionTo);
+    expect(fromSelection, "ALL - Albanian Lek");
+    expect(toSelection, "ALL - Albanian Lek");
+  });
+
+  test('set the currency rate from API', () async{
+    // Given
+    Currency currency = Currency(fromCurrency, toCurrency, 0.6);
+
+    // When
+    when(repository.getConversationRateFromApi(fromCurrency, toCurrency))
+        .thenAnswer((_) async => currency);
+
+    // Then
+    mainViewModel.setCurrencyRate(fromCurrency, toCurrency);
+    await Future.delayed(const Duration(milliseconds: 100));
+
+    expect((mainViewModel.viewState as HasData).data, currency);
+    expect(mainViewModel.conversionRate, currency.rate);
+  });
+
+  test('currency rate api fails to retrieve data', () async{
+    // Given
+    String errorMessage = "failed to retrieve data";
+
+    // When
+    when(repository.getConversationRateFromApi(fromCurrency, toCurrency))
+        .thenAnswer((_) async => Future.error(HttpException(errorMessage)));
+
+    // Then
+    mainViewModel.setCurrencyRate(fromCurrency, toCurrency);
+    await Future.delayed(const Duration(milliseconds: 100));
+
+    expect((mainViewModel.viewState as HasError).error, errorMessage);
+  });
+
+  test('convert input with correct format', () async{
+    // Given
+    String input = "43";
+    mainViewModel.conversionRate = 6.34;
+
+    // When
+
+    // Then
+    expect(mainViewModel.convertInput(input, SelectionType.conversionFrom), "272.62");
+    expect(mainViewModel.convertInput(input, SelectionType.conversionTo), "6.78");
+  });
+
+  test('convert input with empty input', () async{
+    // Given
+    String input = "";
+    mainViewModel.conversionRate = 6.34;
+
+    // When
+
+    // Then
+    expect(mainViewModel.convertInput(input, SelectionType.conversionFrom), "");
+    expect(mainViewModel.convertInput(input, SelectionType.conversionTo), "");
+  });
+
+  test('convert input with empty input', () async{
+    // Given
+    String input = "45.45564";
+    mainViewModel.conversionRate = 6.34;
+
+    // When
+
+    // Then
+    expect(mainViewModel.convertInput(input, SelectionType.conversionFrom), "288.19");
+    expect(mainViewModel.convertInput(input, SelectionType.conversionTo), "7.17");
+  });
+}