diff --git a/lesson_15/tdd/tdd_app/src/main/java/com/codedifferently/lesson15/Employee.java b/lesson_15/tdd/tdd_app/src/main/java/com/codedifferently/lesson15/Employee.java
index 49aaabbd7..b19231051 100644
--- a/lesson_15/tdd/tdd_app/src/main/java/com/codedifferently/lesson15/Employee.java
+++ b/lesson_15/tdd/tdd_app/src/main/java/com/codedifferently/lesson15/Employee.java
@@ -45,4 +45,15 @@ public double getSalary() {
   public void setSalary(double salary) {
     this.salary = salary;
   }
+
+  public String getDetails() {
+    return "ID: "
+        + this.getId()
+        + ", Name: "
+        + this.getName()
+        + ", Department: "
+        + this.getDepartment()
+        + ", Salary: $"
+        + this.getSalary();
+  }
 }
diff --git a/lesson_15/tdd/tdd_app/src/test/java/com/codedifferently/lesson15/EmployeeManagerTest.java b/lesson_15/tdd/tdd_app/src/test/java/com/codedifferently/lesson15/EmployeeManagerTest.java
new file mode 100644
index 000000000..c630e0ded
--- /dev/null
+++ b/lesson_15/tdd/tdd_app/src/test/java/com/codedifferently/lesson15/EmployeeManagerTest.java
@@ -0,0 +1,48 @@
+package test.java.com.codedifferently.lesson15;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import com.codedifferently.lesson15.Employee;
+import com.codedifferently.lesson15.EmployeeManager;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+class EmployeeManagerTest {
+  private EmployeeManager employeeManager;
+  private Employee employee;
+
+  @BeforeEach
+  public void setUp() {
+    employeeManager = new EmployeeManager();
+    employee = new Employee(1, "Yafiah", "Engineering", 75000.0);
+    employeeManager.addEmployee(employee);
+  }
+
+  @Test
+  public void testAddEmployee() {
+    assertEquals(1, employeeManager.getEmployeeCount());
+  }
+
+  @Test
+  public void testGetEmployee() {
+    assertEquals(employee, employeeManager.getEmployee(1));
+  }
+
+  @Test
+  public void testUpdateEmployee() {
+    Employee updatedEmployee = new Employee(1, "Yafiah", "Engineering", 80000.0);
+    employeeManager.updateEmployee(updatedEmployee);
+    assertEquals(80000.0, employeeManager.getEmployee(1).getSalary());
+  }
+
+  @Test
+  public void testRemoveEmployee() {
+    employeeManager.removeEmployee(1);
+    assertEquals(0, employeeManager.getEmployeeCount());
+  }
+
+  @Test
+  public void testGetEmployeeCount() {
+    assertEquals(1, employeeManager.getEmployeeCount());
+  }
+}
diff --git a/lesson_15/tdd/tdd_app/src/test/java/com/codedifferently/lesson15/EmployeeTest.java b/lesson_15/tdd/tdd_app/src/test/java/com/codedifferently/lesson15/EmployeeTest.java
new file mode 100644
index 000000000..317738b25
--- /dev/null
+++ b/lesson_15/tdd/tdd_app/src/test/java/com/codedifferently/lesson15/EmployeeTest.java
@@ -0,0 +1,65 @@
+package com.codedifferently.lesson15;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class EmployeeTest {
+  private Employee employee;
+
+  @BeforeEach
+  public void setUp() {
+    employee = new Employee(1, "Yafiah", "Engineering", 75000.0);
+  }
+
+  @Test
+  public void testGetId() {
+    assertEquals(1, employee.getId());
+  }
+
+  @Test
+  public void testGetName() {
+    assertEquals("Yafiah", employee.getName());
+  }
+
+  @Test
+  public void testGetDepartment() {
+    assertEquals("Engineering", employee.getDepartment());
+  }
+
+  @Test
+  public void testGetSalary() {
+    assertEquals(75000.0, employee.getSalary());
+  }
+
+  @Test
+  public void testSetId() {
+    employee.setId(2);
+    assertEquals(2, employee.getId());
+  }
+
+  @Test
+  public void testSetName() {
+    employee.setName("Nash");
+    assertEquals("Nash", employee.getName());
+  }
+
+  @Test
+  public void testSetDepartment() {
+    employee.setDepartment("Marketing");
+    assertEquals("Marketing", employee.getDepartment());
+  }
+
+  @Test
+  public void testSetSalary() {
+    employee.setSalary(80000.0);
+    assertEquals(80000.0, employee.getSalary());
+  }
+
+  @Test
+  public void testGetDetails() {
+    String expectedDetails = "ID: 1, Name: Yafiah, Department: Engineering, Salary: $75000.0";
+    assertEquals(expectedDetails, employee.getDetails());
+  }
+}