Add Shortest Job First Scheduling (#3843)

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

@@ -0,0 +1,120 @@
+package com.thealgorithms.scheduling;
+
+import com.thealgorithms.devutils.entities.ProcessDetails;
+import org.junit.jupiter.api.Test;
+
+import java.util.ArrayList;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class SJFSchedulingTest {
+    private  ArrayList<ProcessDetails> process;
+    void initialisation0()
+    {
+
+        process=new ArrayList<>();
+        process.add(new ProcessDetails("1",0 ,6));
+        process.add(new ProcessDetails("2",1,2));
+    }
+    void initialisation1()
+    {
+
+        process=new ArrayList<>();
+        process.add(new ProcessDetails("1",0 ,6));
+        process.add(new ProcessDetails("2",1,2));
+        process.add(new ProcessDetails("3",4 ,3));
+        process.add(new ProcessDetails("4",3,1));
+        process.add(new ProcessDetails("5",6 ,4));
+        process.add(new ProcessDetails("6",5,5));
+    }
+
+    void initialisation2()
+    {
+
+        process=new ArrayList<>();
+        process.add(new ProcessDetails("1",0 ,3));
+        process.add(new ProcessDetails("2",1,2));
+        process.add(new ProcessDetails("3",2 ,1));
+
+    }
+    void initialisation3(){
+        process=new ArrayList<>();
+        process.add(new ProcessDetails("1",0 ,3));
+        process.add(new ProcessDetails("2",5,2));
+        process.add(new ProcessDetails("3",9 ,1));
+    }
+    @Test
+    void constructor()
+    {
+        initialisation0();
+        SJFScheduling a=new SJFScheduling(process);
+         assertEquals( 6,a.processes.get(0).getBurstTime());
+        assertEquals( 2,a.processes.get(1).getBurstTime());
+    }
+
+     @Test
+    void sort()
+    {
+        initialisation1();
+        SJFScheduling a=new SJFScheduling(process);
+        a.sortByArrivalTime();
+        assertEquals("1",a.processes.get(0).getProcessId());
+        assertEquals("2",a.processes.get(1).getProcessId());
+        assertEquals("3",a.processes.get(3).getProcessId());
+        assertEquals("4",a.processes.get(2).getProcessId());
+        assertEquals("5",a.processes.get(5).getProcessId());
+        assertEquals("6",a.processes.get(4).getProcessId());
+
+    }
+
+    @Test
+    void scheduling(){
+        initialisation1();
+        SJFScheduling a=new SJFScheduling(process);
+        a.scheduleProcesses();
+        assertEquals( "1"  , a.schedule.get(0));
+        assertEquals( "4"  , a.schedule.get(1));
+        assertEquals(  "2" , a.schedule.get(2));
+        assertEquals(  "3" , a.schedule.get(3));
+        assertEquals("5"   , a.schedule.get(4));
+        assertEquals(   "6", a.schedule.get(5));
+
+
+    }
+
+    @Test
+    void schedulingOf_TwoProcesses(){
+        initialisation0();
+        SJFScheduling a=new SJFScheduling(process);
+        a.scheduleProcesses();
+        assertEquals( "1"  , a.schedule.get(0));
+        assertEquals( "2"  , a.schedule.get(1));
+    }
+
+    @Test
+    void schedulingOfA_ShortestJobArrivingLast(){
+        initialisation2();
+        SJFScheduling a=new SJFScheduling(process);
+        a.scheduleProcesses();
+        assertEquals( "1"  , a.schedule.get(0));
+        assertEquals( "3"  , a.schedule.get(1));
+        assertEquals( "2"  , a.schedule.get(2));
+    }
+    @Test
+    void scheduling_WithProcessesNotComingBackToBack(){
+        initialisation3();
+        SJFScheduling a=new SJFScheduling(process);
+        a.scheduleProcesses();
+        assertEquals( "1"  , a.schedule.get(0));
+        assertEquals( "2"  , a.schedule.get(1));
+        assertEquals( "3"  , a.schedule.get(2));
+    }
+    @Test
+    void schedulingOf_nothing(){
+        process=new ArrayList<>();
+        SJFScheduling a=new SJFScheduling(process);
+        a.scheduleProcesses();
+        assertTrue( a.schedule.isEmpty());
+
+    }
+}