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 49aaabbd..665f0370 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 "Employee 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 00000000..eaa3ab98
--- /dev/null
+++ b/lesson_15/tdd/tdd_app/src/test/java/com/codedifferently/lesson15/EmployeeManagerTest.java
@@ -0,0 +1,73 @@
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+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 cut;
+
+  @BeforeEach
+  public void setUp() {
+    cut = new EmployeeManager();
+    Employee employee1 = new Employee(10, "Jojo", "Sales", 22.12);
+    cut.addEmployee(employee1);
+  }
+
+  @Test
+  public void testAddEmployee() {
+    // Arrange
+    Employee employee = new Employee(2, "Washington", "Finance", 29.23);
+
+    // Act
+    cut.addEmployee(employee);
+
+    // Assert
+    int expectedId = 2;
+    assertEquals(expectedId, cut.getEmployeeCount());
+  }
+
+  @Test
+  public void testUpdateEmployee() {
+    // Arrange
+    Employee employee = new Employee(5, "John", "Safety", 50);
+    cut.addEmployee(employee);
+
+    // Act
+    cut.updateEmployee(employee);
+
+    // Assert
+    int expectedId = 5;
+    assertEquals(expectedId, employee.getId());
+  }
+
+  @Test
+  public void testRemoveEmployee() {
+    // Arrange
+    Employee employee = new Employee(2, "Belvedere", "Finance", 100.1);
+    cut.addEmployee(employee);
+    // Act
+    cut.removeEmployee(employee.getId());
+
+    // Assert
+    int removedId = 2;
+    assertThatThrownBy(() -> cut.removeEmployee(removedId))
+        .isInstanceOf(IllegalArgumentException.class)
+        .hasMessage("Employee does not in collection with id " + removedId);
+  }
+
+  @Test
+  public void testGetEmployee() {
+    // Arrange
+    Employee employee = new Employee(2, "Washington", "Finance", 29.23);
+    // Act
+    cut.addEmployee(employee);
+
+    int employeeId = employee.getId();
+    Employee returnedEmployee = cut.getEmployee(employeeId);
+    // Assert
+    assertEquals(employee, returnedEmployee);
+  }
+}
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 00000000..f869a6c5
--- /dev/null
+++ b/lesson_15/tdd/tdd_app/src/test/java/com/codedifferently/lesson15/EmployeeTest.java
@@ -0,0 +1,79 @@
+package com.codedifferently.lesson15;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+public class EmployeeTest {
+  private Employee cut;
+
+  @BeforeEach
+  public void setUp() {
+    cut = new Employee(1, "Wilmington", "HR", 200.00);
+  }
+
+  @Test
+  public void testGetName() {
+    // Arrange
+    cut.setName("Wilmington");
+
+    // Act
+    String expectedName = cut.getName();
+
+    // Assert
+    String actualName = "Wilmington";
+    assertEquals(expectedName, actualName, "The name should be 'Wilmington'");
+  }
+
+  @Test
+  public void testGetId() {
+    // Arrange
+    cut.setId(1);
+
+    // Act
+    int expectedId = cut.getId();
+
+    // Assert
+    int actualId = 1;
+    assertEquals(expectedId, actualId, "The id should be '1'");
+  }
+
+  @Test
+  public void testGetDepartment() {
+    // Arrange
+    cut.setDepartment("HR");
+
+    // Act
+    String expectedDept = cut.getDepartment();
+
+    // Assert
+    String actualDept = "HR";
+    assertEquals(expectedDept, actualDept, "The Department should be 'HR'");
+  }
+
+  @Test
+  public void testGetSalary() {
+    // Arrange
+    cut.setSalary(200.00);
+
+    // Act
+    double expectedSalary = cut.getSalary();
+
+    // Assert
+    double actualSalary = 200.00;
+    assertEquals(expectedSalary, actualSalary, "The Salary should be '200.00'");
+  }
+
+  @Test
+  public void testGetDetails() {
+    // Arrange
+    String expected = "Employee ID: 1, Name: Wilmington, Department: HR, Salary: 200.0";
+
+    // Act
+    String actual = cut.getDetails();
+
+    // Assert
+    assertEquals(expected, actual);
+  }
+}