Feat: Adds Shawn Dunsmore Jr Lesson 15 Implementing Tests.

lesson_15/tdd/tdd_app/src/main/java/com/codedifferently/lesson15/Employee.java

@@ -45,4 +45,8 @@ public double getSalary() {
   public void setSalary(double salary) {
     this.salary = salary;
   }
+
+  public String getDetails() {
+    return "ID: " + id + ", Name: " + name + ", Department: " + department + ", Salary: " + salary;
+  }
 }

lesson_15/tdd/tdd_app/src/test/java/com/codedifferently/lesson15/Lesson15Test.java

@@ -1,6 +1,7 @@
 package com.codedifferently.lesson15;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
@@ -16,4 +17,74 @@ public void testGetGreeting() {
     // Act
     Lesson15.main(null);
   }
+
+  @Test
+  public void testEmployeeId_Exists() {
+    Employee employee = new Employee(0, null, null, 0);
+    assertEquals(0, employee.getId());
+  }
+
+  @Test
+  public void testEmployeeName_Exists() {
+    Employee employee = new Employee(0, "dave", null, 0);
+    assertEquals("dave", employee.getName());
+  }
+
+  @Test
+  public void testEmployeeDepartment_Exists() {
+    Employee employee = new Employee(0, "dave", "IT", 0);
+    assertEquals("IT", employee.getDepartment());
+  }
+
+  @Test
+  public void testEmployeeSalary_Exists() {
+    Employee employee = new Employee(0, "dave", "IT", 10000);
+    assertEquals(10000, employee.getSalary());
+  }
+
+  @Test
+  public void testGetEmployee() {
+    Employee employee = new Employee(10, null, null, 0);
+    EmployeeManager manager = new EmployeeManager();
+    manager.addEmployee(employee);
+    assertEquals(employee, manager.getEmployee(10));
+  }
+
+  @Test
+  public void testGetEmployeeCount() {
+    Employee employee = new Employee(10, null, null, 0);
+    EmployeeManager manager = new EmployeeManager();
+    manager.addEmployee(employee);
+    assertEquals(1, manager.getEmployeeCount());
+  }
+
+  @Test
+  public void testGetEmployeeUpate() {
+    Employee employee2 = new Employee(10, "BillyBobJenkins", null, 0);
+    Employee employee = new Employee(10, "Dave", null, 0);
+    EmployeeManager manager = new EmployeeManager();
+    manager.addEmployee(employee);
+    manager.updateEmployee(employee2);
+
+    assertEquals(employee2, manager.getEmployee(10));
+  }
+
+  @Test
+  public void testGetEmployeeRemove() {
+    Employee employee2 = new Employee(10, "BillyBobJenkins", null, 0);
+    Employee employee = new Employee(11, "Dave", null, 0);
+    EmployeeManager manager = new EmployeeManager();
+    manager.addEmployee(employee);
+    manager.addEmployee(employee2);
+    manager.removeEmployee(10);
+
+    assertEquals(1, manager.getEmployeeCount());
+  }
+
+  @Test
+  public void testGetDetails() {
+    Employee employee2 = new Employee(10, "BillyBobJenkins", "IT", 10);
+    assertEquals(
+        "ID: 10, Name: BillyBobJenkins, Department: IT, Salary: 10.0", employee2.getDetails());
+  }
 }