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..8062f455f 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
@@ -5,6 +5,7 @@ public class Employee {
   private String name;
   private String department;
   private double salary;
+  Employee employee;
 
   public Employee(int id, String name, String department, double salary) {
     this.id = id;
@@ -45,4 +46,8 @@ public double getSalary() {
   public void setSalary(double salary) {
     this.salary = salary;
   }
+
+  public String getDetails() {
+    return "id " + id + " name " + name + " department " + department + " salary " + salary;
+  }
 }
diff --git a/lesson_15/tdd/tdd_app/src/test/java/EmployeeManagerTest.java b/lesson_15/tdd/tdd_app/src/test/java/EmployeeManagerTest.java
new file mode 100644
index 000000000..ad9082643
--- /dev/null
+++ b/lesson_15/tdd/tdd_app/src/test/java/EmployeeManagerTest.java
@@ -0,0 +1,41 @@
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import com.codedifferently.lesson15.Employee;
+import com.codedifferently.lesson15.EmployeeManager;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class EmployeeManagerTest {
+
+  private EmployeeManager employeeManager;
+  Employee employee;
+  Employee employeeNew;
+
+  @BeforeEach
+  void beforeTest() {
+    employee = new Employee(4, "Dasia", "HR", 100000);
+    employeeManager = new EmployeeManager();
+  }
+
+  @Test
+  void addEmployee() {
+    employeeManager.addEmployee(employee);
+    assertThat(employeeManager.getEmployee(employee.getId())).isEqualTo(employee);
+  }
+
+  @Test
+  void removeEmployee() {
+    employeeManager.addEmployee(employee);
+    employeeManager.removeEmployee(employee.getId());
+    assertEquals(0, employeeManager.getEmployeeCount());
+  }
+
+  @Test
+  void testUpdateEmployee_replacesOutdatedInformation() {
+    employeeManager.addEmployee(employee);
+    employeeNew = new Employee(4, "Bri", "Makerting", 300000);
+    employeeManager.updateEmployee(employeeNew);
+    assertEquals(employeeNew, employeeManager.getEmployee(employee.getId()));
+  }
+}
diff --git a/lesson_15/tdd/tdd_app/src/test/java/EmployeeTest.java b/lesson_15/tdd/tdd_app/src/test/java/EmployeeTest.java
new file mode 100644
index 000000000..383cf93ae
--- /dev/null
+++ b/lesson_15/tdd/tdd_app/src/test/java/EmployeeTest.java
@@ -0,0 +1,65 @@
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import com.codedifferently.lesson15.Employee;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+class EmployeeTest {
+
+  Employee employee;
+
+  @BeforeEach
+  void beforeTest_makesEmployeeBeforeEachTest() {
+    employee = new Employee(4, "Dasia", "Human Resources", 100000);
+  }
+
+  @Test
+  void testgetId() {
+    assertEquals(4, employee.getId());
+  }
+
+  @Test
+  void testsetId_getsEmployeesNewId() {
+    employee.setId(10);
+    assertEquals(10, employee.getId());
+  }
+
+  @Test
+  void testgetName() {
+    assertEquals("Dasia", employee.getName());
+  }
+
+  @Test
+  void testsetName_getsEmployeesNewName() {
+    employee.setName("Destiny");
+    assertEquals("Destiny", employee.getName());
+  }
+
+  @Test
+  void testgetDapartment() {
+    assertEquals("Human Resources", employee.getDepartment());
+  }
+
+  @Test
+  void testsetDepartment_getsEmployeesNewDepartment() {
+    employee.setDepartment("Human Resources");
+    assertEquals("Human Resources", employee.getDepartment());
+  }
+
+  @Test
+  void testgetSalary() {
+    assertEquals(100000, employee.getSalary());
+  }
+
+  @Test
+  void testsetSalary_getsEmployeesNewSalary() {
+    employee.setSalary(100000);
+    assertEquals(100000, employee.getSalary());
+  }
+
+  @Test
+  public void testGetDetails_getEmployeesUniqueInformation() {
+    assertEquals(
+        "id 4 name Dasia department Human Resources salary 100000.0", employee.getDetails());
+  }
+}