add testcase to Optional

Author: javajigi

src/main/java/next/optional/Computer.java

@@ -1,10 +1,11 @@
 package next.optional;
 
+import java.util.Optional;
+
 public class Computer {
 	private Soundcard soundcard;
 
 	public Computer(Soundcard soundcard) {
-		super();
 		this.soundcard = soundcard;
 	}
 

src/main/java/next/optional/ComputerStore.java

@@ -3,6 +3,8 @@
 import next.optional.Computer.Soundcard;
 import next.optional.Computer.USB;
 
+import java.util.Optional;
+
 public class ComputerStore {
 	public static final String UNKNOWN_VERSION = "UNKNOWN";
 

src/test/java/next/optional/ComputerStoreTest.java

@@ -8,7 +8,6 @@
 import next.optional.Computer.USB;
 
 public class ComputerStoreTest {
-
 	@Test
 	public void getVersion() {
 		String version = "pobi's usb";
@@ -33,4 +32,29 @@ public void getVersionWhenUSBIsNull() throws Exception {
 		Computer computer = new Computer(new Soundcard(null));
 		assertThat(ComputerStore.getVersion(computer)).isEqualTo(ComputerStore.UNKNOWN_VERSION);
 	}
+
+	@Test
+	public void getVersionOptional() {
+		String version = "pobi's usb";
+		Soundcard soundcard = new Soundcard(new USB(version));
+		Computer computer = new Computer(soundcard);
+		assertThat(ComputerStore.getVersionOptional(computer)).isEqualTo(version);
+	}
+
+	@Test
+	public void getVersionOptionalWhenComputerIsNull() throws Exception {
+		assertThat(ComputerStore.getVersionOptional(null)).isEqualTo(ComputerStore.UNKNOWN_VERSION);
+	}
+
+	@Test
+	public void getVersionOptionalWhenSoundcardIsNull() throws Exception {
+		Computer computer = new Computer(null);
+		assertThat(ComputerStore.getVersionOptional(computer)).isEqualTo(ComputerStore.UNKNOWN_VERSION);
+	}
+
+	@Test
+	public void getVersionOptionalWhenUSBIsNull() throws Exception {
+		Computer computer = new Computer(new Soundcard(null));
+		assertThat(ComputerStore.getVersionOptional(computer)).isEqualTo(ComputerStore.UNKNOWN_VERSION);
+	}
 }