Wrote test cases for the methods defined

src/main/java/ApplicationDao.java

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+import java.util.List;
+
+public class ApplicationDao {
+    public User getUserById(String id) {
+        if(id.equals("3412"))
+            return null;
+//        Make database query and return a list of users
+        User user = new User();
+        user.setUsername("mark");
+        user.setPassword("name123");
+        user.initializePosts();
+        user.addPost("It's a beautiful day");
+        return user;
+    }
+
+    public void save(User user) throws Exception {
+//        Save entry into db
+//        throws exception if user obj is null
+        if(user == null)
+            throw new Exception("The user is null");
+        System.out.println("User saved successfully");
+    }
+}

src/main/java/Basics.java

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+public class Basics {
+    public int compare(int n1, int n2) {
+        if (n1 > n2) return 1;
+        else if (n1 < n2) return -1;
+        return 0;
+    }
+
+    public int max(int[] arr) {
+        if(arr.length == 0) return -1;
+
+        int max = arr[0];
+        for (int i = 1; i < arr.length; i++) {
+            if (arr[i] > max) {
+                max = arr[i];
+            }
+        }
+        return max;
+    }
+
+    public void sortArray(int[] array) {
+        int n = array.length;
+        for (int i = 0; i < n-1; i++) {
+            for (int j = 0; j < n-i-1; j++) {
+                if (array[j] > array[j+1]) {
+                    int temp = array[j];
+                    array[j] = array[j+1];
+                    array[j+1] = temp;
+                }
+            }
+        }
+    }
+
+    public String reverseString(String s) {
+        int length = s.length();
+        StringBuilder reversed = new StringBuilder(length);
+
+        for (int i = length - 1; i >= 0; i--) {
+            reversed.append(s.charAt(i));
+        }
+
+        return reversed.toString();
+    }
+
+
+
+
+
+}

src/main/java/Mocking.java

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+public class Mocking {
+
+    User user;
+
+
+    public void setUser(User user) {
+        this.user = getUser(user);
+    }
+
+    private User getUser(User user) {
+        return user;
+    }
+
+    public int assignPermission() {
+        if(user.getRole().equals("admin")) {
+            String username = user.getUsername();
+            System.out.println("Assign special permissions for user " + username);
+            return 1;
+        } else {
+            System.out.println("Cannot assign permission");
+            return -1;
+        }
+    }
+
+    public int updateUsername(String id, String username) throws Exception{
+            ApplicationDao applicationDao = new ApplicationDao();
+            User user = applicationDao.getUserById(id);
+            if(user!=null)
+                user.setUsername(username);
+            applicationDao.save(user);
+            return 1;
+    }
+
+
+
+}

src/main/java/User.java

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+import java.util.ArrayList;
+import java.util.List;
+
+public class User {
+    private String id;
+    private String username;
+    private String password;
+    private String role;
+
+
+    public String getId() {
+        return id;
+    }
+
+    public String getRole() {
+        return role;
+    }
+
+    private List<String> posts;
+
+    public String getUsername() {
+        return username;
+    }
+
+    public void setUsername(String username) {
+        this.username = username;
+    }
+
+    public void setPassword(String password) {
+        this.password = password;
+    }
+
+    public List<String> getPosts() {
+        return posts;
+    }
+
+    public void initializePosts() { posts = new ArrayList<>(); }
+
+    public void addPost(String post) {
+        posts.add(post);
+    }
+
+    public List<String> getAllPostsContainingWord(String word) {
+        List<String> filteredPosts = new ArrayList<>();
+        for(String post: posts) {
+            if(post.contains(word))
+                filteredPosts.add(post);
+        }
+        return filteredPosts;
+    }
+}

src/main/java/Welcome.java

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+public class Welcome {
+    public static void main(String[] args) {
+        System.out.println("Welcome to Testing Tutorial");
+    }
+}

src/test/java/BasicTests.java

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+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+public class BasicTests {
+
+    @Test
+    public void compare() {
+        Basics basicTests = new Basics();
+        int value = basicTests.compare(2, 1);
+        Assertions.assertEquals(1, value);
+    }
+
+    @Test
+    @DisplayName("First number is less than the second")
+    public void compare2() {
+        Basics basicTests = new Basics();
+        int value = basicTests.compare(2, 3);
+        Assertions.assertEquals(-1, value);
+    }
+
+    @Test
+    @DisplayName("First number is equal to the second")
+    public void compare3() {
+        Basics basicTests = new Basics();
+        int value = basicTests.compare(2, 2);
+        Assertions.assertEquals(0, value);
+    }
+
+    @Test
+    @DisplayName("Array sorted")
+    public void sortArray() {
+        Basics basicTests = new Basics();
+        int[] array = {5, 8, 3, 9, 1, 6};
+        basicTests.sortArray(array);
+        Assertions.assertArrayEquals(new int[]{1, 3, 5, 6, 8, 9}, array);
+    }
+
+
+}

src/test/java/MockingTests.java

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+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.mockito.Mockito.*;
+
+@ExtendWith(MockitoExtension.class)
+public class MockingTests {
+
+    Mocking mocking;
+
+    @Mock
+    ApplicationDao applicationDao;
+
+
+    @BeforeEach
+    public void setup() {
+//        user = mock(User.class);
+        mocking = new Mocking();
+
+    }
+    @Test
+    @DisplayName("Permission assigned successfully")
+    public void assignPermissions() {
+        User user = mock(User.class);
+        mocking.setUser(user);
+        when(user.getRole()).thenReturn("admin");
+        when(user.getUsername()).thenReturn("kunal");
+        Assertions.assertEquals(1, mocking.assignPermission());
+
+//        Test Method Stubbing for explanation
+//        List<String> filteredPosts = new ArrayList<>();
+//        filteredPosts.add("Awesome Day");
+//        filteredPosts.add("This place is awesome");
+//        when(user.getAllPostsContainingWord("awesome")).thenReturn(filteredPosts);
+    }
+
+    @Test
+    @DisplayName("User updated successfully")
+    public void updateUsername() throws Exception {
+        User user = new User();
+        user.setUsername("kunal");
+        lenient().when(applicationDao.getUserById(Mockito.anyString())).thenReturn(user);
+        Assertions.assertEquals(1, mocking.updateUsername("3211", "allan"));
+    }
+
+    @Test
+    @DisplayName("User could not be updated")
+    public void updateUsernameError() throws Exception {
+        lenient().when(applicationDao.getUserById(Mockito.anyString())).thenReturn(null);
+        Assertions.assertThrows(Exception.class, () -> {
+            mocking.updateUsername("3412","allan");
+        });
+    }
+}