Add tests and implement CompanyEmployee class

Removed OptionalExceptionDemo file and added new test cases for sorting a list and the CompanyEmployee class. Updated build.gradle to use the latest JUnit version. Additionally, fixed a minor issue in FlatMapDemo related to checking for empty orders.

build.gradle

@@ -14,7 +14,7 @@ repositories {
 }
 
 dependencies {
-    testImplementation('org.junit.jupiter:junit-jupiter:5.10.3')
+    testImplementation('org.junit.jupiter:junit-jupiter:5.11.0')
     testImplementation 'org.assertj:assertj-core:3.26.3'
 
     testRuntimeOnly("org.junit.platform:junit-platform-launcher")

src/main/java/interfaces/CompanyEmployee.java

@@ -0,0 +1,30 @@
+package interfaces;
+
+public class CompanyEmployee implements Company, Employee {
+    private final String first;
+    private final String last;
+
+    public CompanyEmployee(String first, String last) {
+        this.first = first;
+        this.last = last;
+    }
+
+    public String getName() {
+        return "%s works for %s".formatted(Employee.super.getName(), Company.super.getName());
+    }
+
+    @Override
+    public String getFirst() {
+        return first;
+    }
+
+    @Override
+    public String getLast() {
+        return last;
+    }
+
+    @Override
+    public void doWork() {
+        System.out.println("Converting caffeine into code for $$$");
+    }
+}

src/main/java/streams/FlatMapDemo.java

@@ -44,9 +44,8 @@ public static void main(String[] args) {
         //      stream() on an empty collection already returns an empty stream
         customers.stream()
                 .flatMap(customer ->
-                        customer.getOrders().size() == 0 ? Stream.empty() :
+                        customer.getOrders().isEmpty() ? Stream.empty() :
                                 customer.getOrders().stream())
                 .forEach(System.out::println);
-
     }
 }

src/test/java/interfaces/CompanyEmployeeTest.java

@@ -2,6 +2,8 @@
 
 import org.junit.jupiter.api.Test;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
 // Create a class called CompanyEmployee that implements both
 //   the Company and Employee interfaces
 // Implement the necessary methods
@@ -11,7 +13,7 @@ public class CompanyEmployeeTest {
 
     @Test
     public void getName() {
-//        CompanyEmployee emp = new CompanyEmployee("Peter", "Gibbons");
-//        assertEquals("Peter Gibbons works for Initech", emp.getName());
+        CompanyEmployee emp = new CompanyEmployee("Peter", "Gibbons");
+        assertEquals("Peter Gibbons works for Initech", emp.getName());
     }
 }

src/test/java/streams/SortListTest.java

@@ -0,0 +1,24 @@
+package streams;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+import java.util.stream.Collectors;
+
+public class SortListTest {
+    private final List<String> list =
+            List.of("banana", "apple", "orange", "kiwi", "grape");
+
+    @Test
+    void sortList_collections() {
+        // throws UnsupportedOperationException because
+        // List.of() returns an unmodifiable list
+//        Collections.sort(list);
+//        System.out.println(list);
+        List<String> sorted = list.stream()
+                .sorted()
+                .collect(Collectors.toList());
+        System.out.println(sorted);
+        System.out.println(list);
+    }
+}