Fix

Author: Hardvan

src/main/java/com/thealgorithms/scheduling/SpeculativeExecutionScheduling.java

@@ -19,15 +19,25 @@ public final class SpeculativeExecutionScheduling {
     static class Task {
         String name;
         boolean completed;
+        long startTime;
 
         Task(String name) {
             this.name = name;
             this.completed = false;
+            this.startTime = -1;
+        }
+
+        void start() {
+            this.startTime = System.currentTimeMillis();
         }
 
         void complete() {
             this.completed = true;
         }
+
+        boolean hasStarted() {
+            return this.startTime != -1;
+        }
     }
 
     private final Map<String, List<Task>> taskGroups;
@@ -48,7 +58,7 @@ public void addTask(String groupName, String taskName) {
     }
 
     /**
-     * Executes the tasks in the specified group.
+     * Executes the tasks in the specified group by assigning a start time.
      *
      * @param groupName the name of the group
      * @return the name of the task that completed successfully
@@ -60,8 +70,11 @@ public String executeTasks(String groupName) {
         }
         for (Task task : tasks) {
             if (!task.completed) {
+                if (!task.hasStarted()) {
+                    task.start();
+                }
                 task.complete();
-                return task.name;
+                return task.name + " started at " + task.startTime;
             }
         }
         return null;

src/test/java/com/thealgorithms/scheduling/SpeculativeExecutionSchedulingTest.java

@@ -2,6 +2,7 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
@@ -18,28 +19,48 @@ public void setup() {
     @Test
     public void testAddAndExecuteTask() {
         scheduler.addTask("Group1", "Task1");
-        assertEquals("Task1", scheduler.executeTasks("Group1"));
+
+        String result = scheduler.executeTasks("Group1");
+        String[] parts = result.split(" started at ");
+
+        // Validate task name and ensure start time is a valid timestamp
+        assertEquals("Task1", parts[0]);
+        assertTrue(Long.parseLong(parts[1]) > 0, "Start time should be greater than 0");
     }
 
     @Test
     public void testMultipleTasksInGroup() {
         scheduler.addTask("Group1", "Task1");
         scheduler.addTask("Group1", "Task2");
-        assertEquals("Task1", scheduler.executeTasks("Group1"));
-        assertEquals("Task2", scheduler.executeTasks("Group1"));
+
+        // Execute the first task
+        String result1 = scheduler.executeTasks("Group1");
+        String[] parts1 = result1.split(" started at ");
+        assertEquals("Task1", parts1[0]);
+        assertTrue(Long.parseLong(parts1[1]) > 0, "Start time should be greater than 0");
+
+        // Execute the second task
+        String result2 = scheduler.executeTasks("Group1");
+        String[] parts2 = result2.split(" started at ");
+        assertEquals("Task2", parts2[0]);
+        assertTrue(Long.parseLong(parts2[1]) > 0, "Start time should be greater than 0");
     }
 
     @Test
     public void testExecuteAllTasks() {
         scheduler.addTask("Group1", "Task1");
         scheduler.addTask("Group1", "Task2");
+
         scheduler.executeTasks("Group1");
         scheduler.executeTasks("Group1");
+
+        // Confirm no tasks remain
         assertNull(scheduler.executeTasks("Group1"));
     }
 
     @Test
     public void testEmptyTaskGroup() {
+        // Confirm executing tasks on an empty group returns null
         assertNull(scheduler.executeTasks("Group2"));
     }
 }