diff --git a/app/navigators/AppNavigator.js b/app/navigators/AppNavigator.js
index d3baa1c..5a3f924 100644
--- a/app/navigators/AppNavigator.js
+++ b/app/navigators/AppNavigator.js
@@ -3,7 +3,7 @@ import { createStackNavigator } from '@react-navigation/stack';
 import SplashScreen from '@scenes/SplashScreen/';
 import ExampleScreen from '@scenes/ExampleScreen';
 import { NavigationContainer } from '@react-navigation/native';
-import NavigationService from '../services/NavigationService';
+import { setTopLevelNavigator } from '@app/services/NavigationService';
 const Stack = createStackNavigator();
 /**
  * The root screen contains the application's navigation.
@@ -12,7 +12,7 @@ const Stack = createStackNavigator();
  */
 export default function AppNavigator() {
   return (
-    <NavigationContainer ref={NavigationService.setTopLevelNavigator}>
+    <NavigationContainer ref={setTopLevelNavigator}>
       <Stack.Navigator headerMode="none" initialRouteName="SplashScreen">
         <Stack.Screen name="SplashScreen" component={SplashScreen} />
         <Stack.Screen name="MainScreen" component={ExampleScreen} />
diff --git a/app/scenes/ExampleScreen/saga.js b/app/scenes/ExampleScreen/saga.js
index 618d25a..a0eefa1 100644
--- a/app/scenes/ExampleScreen/saga.js
+++ b/app/scenes/ExampleScreen/saga.js
@@ -1,6 +1,6 @@
 import { put, call, takeLatest } from 'redux-saga/effects';
 import { get } from 'lodash';
-import { getUser } from '@app/services/UserService';
+import { getUser } from '@app/services/userService';
 import { exampleScreenActions, exampleScreenTypes } from './reducer';
 
 /**
diff --git a/app/scenes/ExampleScreen/tests/saga.test.js b/app/scenes/ExampleScreen/tests/saga.test.js
index 5745a97..5001a40 100644
--- a/app/scenes/ExampleScreen/tests/saga.test.js
+++ b/app/scenes/ExampleScreen/tests/saga.test.js
@@ -5,7 +5,7 @@
 /* eslint-disable redux-saga/yield-effects */
 
 import { takeLatest, call, put } from 'redux-saga/effects';
-import { getUser } from 'app/services/UserService';
+import { getUser } from '@app/services/userService';
 import { apiResponseGenerator } from 'app/utils/testUtils';
 import exampleScreenSaga, { fetchUser } from '../saga';
 import { exampleScreenTypes } from '../reducer';
diff --git a/app/scenes/RootScreen/tests/saga.test.js b/app/scenes/RootScreen/tests/saga.test.js
index 0bed1dc..10e90c9 100644
--- a/app/scenes/RootScreen/tests/saga.test.js
+++ b/app/scenes/RootScreen/tests/saga.test.js
@@ -5,21 +5,22 @@
 /* eslint-disable redux-saga/yield-effects */
 
 import { takeLatest } from 'redux-saga/effects';
-import NavigationService from 'app/services/NavigationService';
+import { navigateAndReset } from '@app/services/NavigationService';
 import { timeout } from 'app/utils/testUtils';
 import rootScreenSaga, { startup } from '../saga';
 import { rootScreenTypes } from '../reducer';
 
+jest.mock('@app/services/NavigationService', () => ({
+  ...jest.requireActual('@app/services/NavigationService'),
+  navigateAndReset: jest.fn()
+}));
 describe('Tests for RootScreen sagas', () => {
-  let generator;
-  let submitSpy;
-
-  beforeEach(() => {
-    generator = rootScreenSaga();
-    submitSpy = jest.fn();
+  afterEach(() => {
+    jest.clearAllMocks();
   });
 
   it('should start task to watch for STARTUP action', () => {
+    const generator = rootScreenSaga();
     expect(generator.next().value).toEqual(
       takeLatest(rootScreenTypes.STARTUP, startup)
     );
@@ -27,19 +28,18 @@ describe('Tests for RootScreen sagas', () => {
 
   it('should ensure that the navigation service is called after waiting for 1000ms', async () => {
     const method = startup();
-    NavigationService.navigateAndReset = submitSpy;
     method.next();
     await timeout(1000);
-    expect(submitSpy).toHaveBeenCalled();
+    expect(navigateAndReset).toHaveBeenCalled();
+    expect(navigateAndReset).toHaveBeenCalledWith('MainScreen');
   });
 
   it('should ensure that the navigation service is called after waiting for 1000ms', async () => {
     const method = startup();
-    NavigationService.navigateAndReset = submitSpy;
     method.next();
     await timeout(650);
-    expect(submitSpy).not.toHaveBeenCalled();
+    expect(navigateAndReset).not.toHaveBeenCalled();
     await timeout(200);
-    expect(submitSpy).not.toHaveBeenCalled();
+    expect(navigateAndReset).not.toHaveBeenCalled();
   });
 });
diff --git a/app/services/NavigationService.js b/app/services/NavigationService.js
index 49c90a2..147f778 100644
--- a/app/services/NavigationService.js
+++ b/app/services/NavigationService.js
@@ -1,19 +1,21 @@
 import { NavigationActions, StackActions } from '@react-navigation/compat';
-
+import set from 'lodash/set';
 /**
  * The navigation is implemented as a service so that it can be used outside of components, for example in sagas.
  *
  * @see https://reactnavigation.org/docs/en/navigating-without-navigation-prop.html
  */
 
-let navigator;
+const navigatorObject = {
+  navigator: null
+};
 
 /**
  * This function is called when the RootScreen is created to set the navigator instance to use.
  */
-function setTopLevelNavigator(navigatorRef) {
-  navigator = navigatorRef;
-}
+const setTopLevelNavigator = navigatorRef => {
+  set(navigatorObject, 'navigator', navigatorRef);
+};
 
 /**
  * Call this function when you want to navigate to a specific route.
@@ -22,7 +24,7 @@ function setTopLevelNavigator(navigatorRef) {
  * @param params Route parameters.
  */
 function navigate(routeName, params) {
-  navigator.dispatch(
+  navigatorObject.navigator.dispatch(
     NavigationActions.navigate({
       routeName,
       params
@@ -40,7 +42,7 @@ function navigate(routeName, params) {
  * @param params Route parameters.
  */
 function navigateAndReset(routeName, params) {
-  navigator.dispatch(
+  navigatorObject.navigator.dispatch(
     StackActions.replace({
       routeName,
       params
@@ -48,8 +50,4 @@ function navigateAndReset(routeName, params) {
   );
 }
 
-export default {
-  navigate,
-  navigateAndReset,
-  setTopLevelNavigator
-};
+export { navigate, navigateAndReset, setTopLevelNavigator };
diff --git a/app/services/tests/navigate.test.js b/app/services/tests/navigate.test.js
new file mode 100644
index 0000000..23fa7a6
--- /dev/null
+++ b/app/services/tests/navigate.test.js
@@ -0,0 +1,32 @@
+import { NavigationActions } from '@react-navigation/compat';
+import { navigate, setTopLevelNavigator } from '../NavigationService';
+jest.mock('@react-navigation/compat', () => ({
+  NavigationActions: {
+    navigate: jest.fn()
+  }
+}));
+const navigatorRef = { goBack: 'goBack', dispatch: jest.fn() };
+setTopLevelNavigator(navigatorRef);
+describe('navigate', () => {
+  afterEach(() => {
+    jest.clearAllMocks();
+  });
+
+  it('dispatches navigation action with the correct routeName and params', () => {
+    const routeName = '/test';
+    const params = { screen: 'MainScreen' };
+    NavigationActions.navigate.mockReturnValueOnce({
+      type: 'NAVIGATE_ACTION',
+      payload: { routeName, params }
+    });
+    navigate(routeName, params);
+    expect(NavigationActions.navigate).toHaveBeenCalledWith({
+      routeName,
+      params
+    });
+    expect(navigatorRef.dispatch).toHaveBeenCalledWith({
+      type: 'NAVIGATE_ACTION',
+      payload: { routeName, params }
+    });
+  });
+});
diff --git a/app/services/tests/navigateAndReset.test.js b/app/services/tests/navigateAndReset.test.js
new file mode 100644
index 0000000..edbc7b7
--- /dev/null
+++ b/app/services/tests/navigateAndReset.test.js
@@ -0,0 +1,34 @@
+import { StackActions } from '@react-navigation/compat';
+import { setTopLevelNavigator, navigateAndReset } from '../NavigationService';
+
+jest.mock('@react-navigation/compat', () => ({
+  StackActions: {
+    replace: jest.fn()
+  }
+}));
+const navigatorRef = { goBack: 'goBack', dispatch: jest.fn() };
+setTopLevelNavigator(navigatorRef);
+describe('test navigateAndReset', () => {
+  afterEach(() => {
+    // Reset mocks after each test
+    jest.clearAllMocks();
+  });
+
+  it('dispatches stack action with the correct routeName and params', () => {
+    const routeName = '/test';
+    const params = { screen: 'MainScreen' };
+    StackActions.replace.mockReturnValueOnce({
+      type: 'NAVIGATE_ACTION',
+      payload: { routeName, params }
+    });
+    navigateAndReset(routeName, params);
+    expect(StackActions.replace).toHaveBeenCalledWith({
+      routeName,
+      params
+    });
+    expect(navigatorRef.dispatch).toHaveBeenCalledWith({
+      type: 'NAVIGATE_ACTION',
+      payload: { routeName, params }
+    });
+  });
+});
diff --git a/app/services/tests/setTopLevelNavigation.test.js b/app/services/tests/setTopLevelNavigation.test.js
new file mode 100644
index 0000000..4d4e62a
--- /dev/null
+++ b/app/services/tests/setTopLevelNavigation.test.js
@@ -0,0 +1,20 @@
+import set from 'lodash/set';
+import { setTopLevelNavigator } from '@app/services/NavigationService';
+jest.mock('lodash/set', () => jest.fn());
+describe('setTopLevelNavigator', () => {
+  afterEach(() => {
+    jest.clearAllMocks();
+  });
+  it('sets the navigator object with the provided reference', () => {
+    const navigatorObject = {
+      navigator: null
+    };
+    const navigatorRef = { goBack: 'goBack' };
+    setTopLevelNavigator(navigatorRef);
+    expect(set).toHaveBeenCalledWith(
+      navigatorObject,
+      'navigator',
+      navigatorRef
+    );
+  });
+});
diff --git a/app/services/UserService.test.js b/app/services/tests/userService.test.js
similarity index 94%
rename from app/services/UserService.test.js
rename to app/services/tests/userService.test.js
index 53cbead..fc453f5 100644
--- a/app/services/UserService.test.js
+++ b/app/services/tests/userService.test.js
@@ -1,6 +1,6 @@
 import MockAdapter from 'axios-mock-adapter';
 import { getApiClient } from 'app/utils/apiUtils';
-import { getUser } from './UserService';
+import { getUser } from '../userService';
 
 describe('UserService tests', () => {
   it('should make the api call to "/quotes?count=1"', async () => {