Add fcfs scheduling (#3335)

Co-authored-by: Smiti <smmaheshwari@paypal.com>

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

@@ -0,0 +1,50 @@
+package com.thealgorithms.scheduling;
+
+import com.thealgorithms.devutils.entities.ProcessDetails;
+import org.junit.jupiter.api.Test;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class FCFSSchedulingTest {
+
+
+    @Test
+    public void testingProcesses() {
+        List<ProcessDetails> processes = addProcessesForFCFS();
+        final FCFSScheduling fcfsScheduling = new FCFSScheduling(processes); // for sending to FCFS
+
+        fcfsScheduling.scheduleProcesses();
+
+        assertEquals(3, processes.size());
+
+        assertEquals("P1", processes.get(0).getProcessId());
+        assertEquals(0, processes.get(0).getWaitingTime());
+        assertEquals(10, processes.get(0).getTurnAroundTimeTime());
+
+        assertEquals("P2", processes.get(1).getProcessId());
+        assertEquals(10, processes.get(1).getWaitingTime());
+        assertEquals(15, processes.get(1).getTurnAroundTimeTime());
+
+        assertEquals("P3", processes.get(2).getProcessId());
+        assertEquals(15, processes.get(2).getWaitingTime());
+        assertEquals(23, processes.get(2).getTurnAroundTimeTime());
+
+    }
+
+    private List<ProcessDetails> addProcessesForFCFS() {
+        final ProcessDetails process1 = new ProcessDetails("P1", 0, 10);
+        final ProcessDetails process2 = new ProcessDetails("P2", 1, 5);
+        final ProcessDetails process3 = new ProcessDetails("P3", 2, 8);
+
+        final List<ProcessDetails> processDetails = new ArrayList<>();
+        processDetails.add(process1);
+        processDetails.add(process2);
+        processDetails.add(process3);
+
+        return processDetails;
+    }
+
+}