New tested Stopwatch :D

src/Stopwatch/StopWatch.java

@@ -0,0 +1,36 @@
+package Stopwatch;
+
+import java.time.LocalTime;
+import java.time.temporal.ChronoUnit;
+
+public class StopWatch
+{
+    private LocalTime startTime,endTime;
+    StopWatch()
+    {
+        startTime=LocalTime.of(0,0,0);
+        endTime= LocalTime.of(0,0,0);
+    }
+    public LocalTime getStartTime()
+    {
+        return startTime;
+    }
+    public LocalTime getEndTime()
+    {
+        return endTime;
+    }
+    public LocalTime start()
+    {
+       return startTime=LocalTime.now();
+    }
+    public LocalTime stop()
+    {
+        return endTime=LocalTime.now();
+    }
+    public Long getElapsedTime()
+    {
+        Long milliesbetween= ChronoUnit.MILLIS.between(startTime,endTime);
+        return (milliesbetween);
+    }
+
+}

src/Stopwatch/StopWatchTest.java

@@ -0,0 +1,53 @@
+package Stopwatch;
+
+import org.junit.Test;
+
+import java.util.concurrent.TimeUnit;
+
+import static org.junit.Assert.*;
+
+public class StopWatchTest
+{
+
+    @Test
+    public void getElapsedTime() throws InterruptedException
+    {
+       StopWatch Watch1 = new StopWatch();
+       StopWatch Watch2 = new StopWatch();
+       StopWatch Watch3 = new StopWatch();
+       StopWatch Watch4 = new StopWatch();
+        Watch1.start();
+        try
+        {
+            TimeUnit.MINUTES.sleep(1);
+        }
+        catch (InterruptedException e)
+        {
+            e.printStackTrace();
+        }
+        Watch1.stop();
+
+        Watch2.start();
+        TimeUnit.MILLISECONDS.sleep(69);
+        Watch2.stop();
+
+        Watch3.start();
+        TimeUnit.MILLISECONDS.sleep(10);
+        Watch3.stop();
+
+        Watch4.start();
+        TimeUnit.MILLISECONDS.sleep(12);
+        Watch4.start();
+        TimeUnit.MILLISECONDS.sleep(69);
+        Watch4.stop();
+
+
+
+        assertEquals(60000, Watch1.getElapsedTime(), 10);
+        assertEquals(69, Watch2.getElapsedTime(),10);
+        assertEquals(10, Watch3.getElapsedTime(),10);
+        assertEquals(69, Watch4.getElapsedTime(),10);
+
+
+    }
+}