'Final homework with tests'

lib/model/EnergyModelProvider.dart

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+import 'package:flutter/material.dart';
+
+class EnergyModelProvider with ChangeNotifier {
+  double potentialEnergy = 0,
+      kineticEnergy = 0,
+      energyInJoule = 0,
+      literWaterToHeat = 0,
+      kilogrammIronToHeat = 0;
+
+  EnergyModelProvider() {}
+
+  /// E = kg * (m^2 / s^2)
+  double calculateEnergyInJoule(String weightValue, String velocity) {
+    double weightValueInDouble = double.parse(weightValue);
+    double velocityInDouble = double.parse(velocity);
+
+    energyInJoule = (velocityInDouble * velocityInDouble) / weightValueInDouble;
+    notifyListeners();
+
+    return energyInJoule;
+  }
+
+  ///  E = m * g * h in Joule
+  void calculateEnergyPotential(String weightValue, String altitudeChange) {
+    double weightValueInDouble = double.parse(weightValue);
+    double altitudeChangeInDouble = double.parse(altitudeChange);
+
+    potentialEnergy = weightValueInDouble * 9.81 * altitudeChangeInDouble;
+    notifyListeners();
+  }
+
+  /// E = 1/2 * m * v^2 in Joule
+  void calculateEnergyKinetic(String weightValue, String velocity) {
+    double weightValueInDouble = double.parse(weightValue);
+    double velocityInDouble = double.parse(velocity);
+
+    kineticEnergy =
+        0.5 * weightValueInDouble * (velocityInDouble * velocityInDouble);
+    notifyListeners();
+  }
+
+  /**
+   * E = c * m * delta T
+   * c = spezifische Wärmekapazität Wasser 4,182 kJ/l
+   * m = Masse
+   * delta T = Temperaturunterschied
+   */
+  void calculateLiterToHeatWater() {
+    // 4182 J = 1l = 1000kg Waasser um 1° zu erwaermen
+    // E/c/delta T = m
+    //Total Energie = Potentielle Energie + Kinetische Energie
+    literWaterToHeat = (potentialEnergy + kineticEnergy) / (4182 * 80);
+    notifyListeners();
+  }
+
+  void calculateKgToHeatIron() {
+    kilogrammIronToHeat = (potentialEnergy + kineticEnergy) / (460 * 680);
+    notifyListeners();
+  }
+}

test/EnergyModelProvider_test.dart

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+import 'package:energy/model/EnergyModelProvider.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  group('EnergyModelProviderTest1', () {
+    final provider = EnergyModelProvider();
+
+    test('Tests calculateEnergyInJoule', () {
+      provider.calculateEnergyInJoule('100', '500');
+      expect(provider.energyInJoule, 2500.0);
+    });
+
+    test('Tests calculateEnergyPotential', () {
+      provider.calculateEnergyPotential('10', '50');
+      expect(provider.potentialEnergy, 4905.0);
+    });
+
+    test('Tests calculateEnergyPotential', () {
+      provider.calculateEnergyKinetic('10', '50');
+      expect(provider.kineticEnergy, 12500.0);
+    });
+
+    test('Tests calculateEnergyPotential', () {
+      provider.calculateLiterToHeatWater();
+      expect(provider.literWaterToHeat, 0.05202355332376853);
+    });
+
+    test('Tests calculateKgToHeatIron', () {
+      provider.calculateKgToHeatIron();
+      expect(provider.kilogrammIronToHeat, 0.055642583120204606);
+    });
+  });
+
+  group('EnergyProviderTest2', () {
+    final provider = EnergyModelProvider();
+
+    test('Tests calculateEnergyInJoule', () {
+      provider.calculateEnergyInJoule('5000', '180');
+      expect(provider.energyInJoule, 6.48);
+    });
+
+    test('Tests calculateEnergyPotential', () {
+      provider.calculateEnergyPotential('5000', '60');
+      expect(provider.potentialEnergy, 2943000.0);
+    });
+
+    test('Tests calculateEnergyPotential', () {
+      provider.calculateEnergyKinetic('2000', '60');
+      expect(provider.kineticEnergy, 3600000.0);
+    });
+
+    test('Tests calculateEnergyPotential', () {
+      provider.calculateLiterToHeatWater();
+      expect(provider.literWaterToHeat, 19.557030129124822);
+    });
+
+    test('Tests calculateKgToHeatIron', () {
+      provider.calculateKgToHeatIron();
+      expect(provider.kilogrammIronToHeat, 20.91751918158568);
+    });
+  });
+}