Refactor IntersectionProcess and add unit tests

main/src/main/java/sd/IntersectionProcess.java

@@ -177,7 +177,7 @@ public class IntersectionProcess {
         
         while (running) {
             try {
-                // GREEN phase
+                // Green state
                 light.changeState(TrafficLightState.GREEN);
                 System.out.println("[" + light.getId() + "] State: GREEN");
                 
@@ -187,7 +187,7 @@ public class IntersectionProcess {
                 // Wait for green duration
                 Thread.sleep((long) (light.getGreenTime() * 1000));
                 
-                // RED phase
+                // RED state
                 light.changeState(TrafficLightState.RED);
                 System.out.println("[" + light.getId() + "] State: RED");
                 
@@ -323,10 +323,8 @@ public class IntersectionProcess {
     private String getHostForDestination(String destinationId) {
         if (destinationId.equals("S")) {
             return config.getExitHost();
-        } else if (destinationId.startsWith("Cr")) {
-            return config.getIntersectionHost(destinationId);
         } else {
-            return config.getDashboardHost();
+            return config.getIntersectionHost(destinationId);
         }
     }
     
@@ -339,10 +337,8 @@ public class IntersectionProcess {
     private int getPortForDestination(String destinationId) {
         if (destinationId.equals("S")) {
             return config.getExitPort();
-        } else if (destinationId.startsWith("Cr")) {
-            return config.getIntersectionPort(destinationId);
         } else {
-            return config.getDashboardPort();
+            return config.getIntersectionPort(destinationId);
         }
     }
     
@@ -465,45 +461,6 @@ public class IntersectionProcess {
         System.out.println("=".repeat(60));
     }
     
-    /**
-     * Main method to start an intersection process.
-     *
-     * @param args Command-line arguments:
-     *             args[0] - Intersection ID (required, e.g., "Cr1")
-     *             args[1] - Config file path (optional, defaults to "simulation.properties")
-     */
-    public static void main(String[] args) {
-        if (args.length < 1) {
-            System.err.println("Usage: java IntersectionProcess <intersectionId> [configFile]");
-            System.err.println("Example: java IntersectionProcess Cr1");
-            System.exit(1);
-        }
-        
-        String intersectionId = args[0];
-        String configFile = args.length > 1 ? args[1] : "simulation.properties";
-        
-        IntersectionProcess process = null;
-        
-        try {
-            process = new IntersectionProcess(intersectionId, configFile);
-            process.initialize();
-            
-            // Add shutdown hook for graceful termination
-            final IntersectionProcess finalProcess = process;
-            Runtime.getRuntime().addShutdownHook(new Thread(() -> {
-                finalProcess.shutdown();
-            }));
-            
-            // Start the process
-            process.start();
-            
-        } catch (IOException e) {
-            System.err.println("Error starting intersection process: " + e.getMessage());
-            e.printStackTrace();
-            System.exit(1);
-        }
-    }
-    
     // --- Inner class for Vehicle Transfer Messages ---
     
     /**

main/src/test/java/IntersectionProcessTest.java

@@ -0,0 +1,473 @@
+import java.io.IOException;
+import java.io.ObjectOutputStream;
+import java.net.Socket;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Arrays;
+
+import org.junit.jupiter.api.AfterEach;
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.Timeout;
+import org.junit.jupiter.api.io.TempDir;
+
+import sd.IntersectionProcess;
+import sd.model.MessageType;
+import sd.model.Vehicle;
+import sd.model.VehicleType;
+
+/**
+ * Tests for IntersectionProcess - covers initialization, traffic lights, 
+ * vehicle transfer and network stuff
+ */
+public class IntersectionProcessTest {
+
+    @TempDir
+    Path tempDir;
+
+    private Path configFile;
+    private IntersectionProcess intersectionProcess;
+
+    // setup test config before each test
+    @BeforeEach
+    public void setUp() throws IOException {
+        // create temp config file
+        configFile = tempDir.resolve("test-simulation.properties");
+        
+        String configContent = """
+                # Test Simulation Configuration
+                
+                # Intersection Network Configuration
+                intersection.Cr1.host=localhost
+                intersection.Cr1.port=18001
+                intersection.Cr2.host=localhost
+                intersection.Cr2.port=18002
+                intersection.Cr3.host=localhost
+                intersection.Cr3.port=18003
+                intersection.Cr4.host=localhost
+                intersection.Cr4.port=18004
+                intersection.Cr5.host=localhost
+                intersection.Cr5.port=18005
+                
+                # Exit Configuration
+                exit.host=localhost
+                exit.port=18099
+                
+                # Dashboard Configuration
+                dashboard.host=localhost
+                dashboard.port=18100
+                
+                # Traffic Light Timing (seconds)
+                trafficLight.Cr1.East.greenTime=5.0
+                trafficLight.Cr1.East.redTime=5.0
+                trafficLight.Cr1.South.greenTime=5.0
+                trafficLight.Cr1.South.redTime=5.0
+                trafficLight.Cr1.West.greenTime=5.0
+                trafficLight.Cr1.West.redTime=5.0
+                
+                trafficLight.Cr2.West.greenTime=4.0
+                trafficLight.Cr2.West.redTime=6.0
+                trafficLight.Cr2.East.greenTime=4.0
+                trafficLight.Cr2.East.redTime=6.0
+                trafficLight.Cr2.South.greenTime=4.0
+                trafficLight.Cr2.South.redTime=6.0
+                
+                trafficLight.Cr3.West.greenTime=3.0
+                trafficLight.Cr3.West.redTime=7.0
+                trafficLight.Cr3.East.greenTime=3.0
+                trafficLight.Cr3.East.redTime=7.0
+                
+                trafficLight.Cr4.East.greenTime=6.0
+                trafficLight.Cr4.East.redTime=4.0
+                
+                trafficLight.Cr5.East.greenTime=5.0
+                trafficLight.Cr5.East.redTime=5.0
+                
+                # Vehicle Crossing Times (seconds)
+                vehicle.bike.crossingTime=2.0
+                vehicle.light.crossingTime=3.0
+                vehicle.heavy.crossingTime=5.0
+                """;
+        
+        Files.writeString(configFile, configContent);
+    }
+
+    // cleanup after tests
+    @AfterEach
+    public void tearDown() {
+        if (intersectionProcess != null) {
+            intersectionProcess.shutdown();
+        }
+    }
+
+    // ==================== Initialization Tests ====================
+
+    @Test
+    public void testConstructor_Success() throws IOException {
+        intersectionProcess = new IntersectionProcess("Cr1", configFile.toString());
+        assertNotNull(intersectionProcess);
+    }
+
+    @Test
+    public void testConstructor_InvalidConfig() {
+        Exception exception = assertThrows(IOException.class, () -> {
+            new IntersectionProcess("Cr1", "non-existent-config.properties");
+        });
+        assertNotNull(exception);
+    }
+
+    @Test
+    public void testInitialize_Cr1() throws IOException {
+        intersectionProcess = new IntersectionProcess("Cr1", configFile.toString());
+        assertDoesNotThrow(() -> intersectionProcess.initialize());
+    }
+
+    @Test
+    public void testInitialize_Cr2() throws IOException {
+        intersectionProcess = new IntersectionProcess("Cr2", configFile.toString());
+        assertDoesNotThrow(() -> intersectionProcess.initialize());
+    }
+
+    @Test
+    public void testInitialize_Cr3() throws IOException {
+        intersectionProcess = new IntersectionProcess("Cr3", configFile.toString());
+        assertDoesNotThrow(() -> intersectionProcess.initialize());
+    }
+
+    @Test
+    public void testInitialize_Cr4() throws IOException {
+        intersectionProcess = new IntersectionProcess("Cr4", configFile.toString());
+        assertDoesNotThrow(() -> intersectionProcess.initialize());
+    }
+
+    @Test
+    public void testInitialize_Cr5() throws IOException {
+        intersectionProcess = new IntersectionProcess("Cr5", configFile.toString());
+        assertDoesNotThrow(() -> intersectionProcess.initialize());
+    }
+
+    // traffic light creation tests
+
+    @Test
+    public void testTrafficLightCreation_Cr1_HasCorrectDirections() throws IOException {
+        intersectionProcess = new IntersectionProcess("Cr1", configFile.toString());
+        intersectionProcess.initialize();
+        
+        // cant access private fields but initialization succeds
+        assertNotNull(intersectionProcess);
+    }
+
+    @Test
+    public void testTrafficLightCreation_Cr3_HasCorrectDirections() throws IOException {
+        intersectionProcess = new IntersectionProcess("Cr3", configFile.toString());
+        intersectionProcess.initialize();
+        
+        // Cr3 has west and south only
+        assertNotNull(intersectionProcess);
+    }
+
+    @Test
+    public void testTrafficLightCreation_Cr4_HasSingleDirection() throws IOException {
+        intersectionProcess = new IntersectionProcess("Cr4", configFile.toString());
+        intersectionProcess.initialize();
+        
+        // Cr4 only has east direction
+        assertNotNull(intersectionProcess);
+    }
+
+    // server startup tests
+
+    @Test
+    @Timeout(5)
+    public void testServerStart_BindsToCorrectPort() throws IOException, InterruptedException {
+        intersectionProcess = new IntersectionProcess("Cr1", configFile.toString());
+        intersectionProcess.initialize();
+        
+        // start server in seperate thread
+        Thread serverThread = new Thread(() -> {
+            try {
+                intersectionProcess.start();
+            } catch (IOException e) {
+                // expected on shutdown
+            }
+        });
+        serverThread.start();
+        
+        Thread.sleep(500); // wait for server to start
+        
+        // try connecting to check if its running
+        try (Socket clientSocket = new Socket("localhost", 18001)) {
+            assertTrue(clientSocket.isConnected());
+        }
+        
+        intersectionProcess.shutdown();
+        serverThread.join(2000);
+    }
+
+    @Test
+    @Timeout(5)
+    public void testServerStart_MultipleIntersections() throws IOException, InterruptedException {
+        // test 2 intersections on diferent ports
+        IntersectionProcess cr1 = new IntersectionProcess("Cr1", configFile.toString());
+        IntersectionProcess cr2 = new IntersectionProcess("Cr2", configFile.toString());
+        
+        cr1.initialize();
+        cr2.initialize();
+        
+        Thread thread1 = new Thread(() -> {
+            try { cr1.start(); } catch (IOException e) { }
+        });
+        
+        Thread thread2 = new Thread(() -> {
+            try { cr2.start(); } catch (IOException e) { }
+        });
+        
+        thread1.start();
+        thread2.start();
+        
+        Thread.sleep(500);
+        
+        // check both are running
+        try (Socket socket1 = new Socket("localhost", 18001);
+             Socket socket2 = new Socket("localhost", 18002)) {
+            assertTrue(socket1.isConnected());
+            assertTrue(socket2.isConnected());
+        }
+        
+        cr1.shutdown();
+        cr2.shutdown();
+        thread1.join(2000);
+        thread2.join(2000);
+    }
+
+    // vehicle transfer tests
+
+    @Test
+    @Timeout(10)
+    public void testVehicleTransfer_ReceiveVehicle() throws IOException, InterruptedException {
+        // setup reciever intersection
+        intersectionProcess = new IntersectionProcess("Cr2", configFile.toString());
+        intersectionProcess.initialize();
+        
+        Thread serverThread = new Thread(() -> {
+            try {
+                intersectionProcess.start();
+            } catch (IOException e) { }
+        });
+        serverThread.start();
+        
+        Thread.sleep(500);
+        
+        // create test vehicle
+        java.util.List<String> route = Arrays.asList("Cr2", "Cr3", "S");
+        Vehicle vehicle = new Vehicle("V001", VehicleType.LIGHT, 0.0, route);
+        
+        // send vehicle from Cr1 to Cr2
+        try (Socket socket = new Socket("localhost", 18002)) {
+            ObjectOutputStream out = new ObjectOutputStream(socket.getOutputStream());
+            
+            TestVehicleMessage message = new TestVehicleMessage("Cr1", "Cr2", vehicle);
+            out.writeObject(message);
+            out.flush();
+            
+            Thread.sleep(1000); // wait for procesing
+        }
+        
+        intersectionProcess.shutdown();
+        serverThread.join(2000);
+    }
+
+    // routing config tests
+
+    @Test
+    public void testRoutingConfiguration_Cr1() throws IOException {
+        intersectionProcess = new IntersectionProcess("Cr1", configFile.toString());
+        intersectionProcess.initialize();
+        
+        // indirect test - if init works routing should be ok
+        assertNotNull(intersectionProcess);
+    }
+
+    @Test
+    public void testRoutingConfiguration_Cr5() throws IOException {
+        intersectionProcess = new IntersectionProcess("Cr5", configFile.toString());
+        intersectionProcess.initialize();
+        
+        // Cr5 routes to exit
+        assertNotNull(intersectionProcess);
+    }
+
+    // shutdown tests
+
+    @Test
+    @Timeout(5)
+    public void testShutdown_GracefulTermination() throws IOException, InterruptedException {
+        intersectionProcess = new IntersectionProcess("Cr1", configFile.toString());
+        intersectionProcess.initialize();
+        
+        Thread serverThread = new Thread(() -> {
+            try {
+                intersectionProcess.start();
+            } catch (IOException e) { }
+        });
+        serverThread.start();
+        
+        Thread.sleep(500);
+        
+        // shutdown should be fast
+        assertDoesNotThrow(() -> intersectionProcess.shutdown());
+        
+        serverThread.join(2000);
+    }
+
+    @Test
+    @Timeout(5)
+    public void testShutdown_ClosesServerSocket() throws IOException, InterruptedException {
+        intersectionProcess = new IntersectionProcess("Cr1", configFile.toString());
+        intersectionProcess.initialize();
+        
+        Thread serverThread = new Thread(() -> {
+            try {
+                intersectionProcess.start();
+            } catch (IOException e) { }
+        });
+        serverThread.start();
+        
+        Thread.sleep(500);
+        
+        // verify server running
+        try (Socket socket = new Socket("localhost", 18001)) {
+            assertTrue(socket.isConnected());
+        }
+        
+        intersectionProcess.shutdown();
+        serverThread.join(2000);
+        
+        // after shutdown conection should fail
+        Thread.sleep(500);
+        Exception exception = assertThrows(IOException.class, () -> {
+            Socket socket = new Socket("localhost", 18001);
+            socket.close();
+        });
+        assertNotNull(exception);
+    }
+
+    @Test
+    @Timeout(5)
+    public void testShutdown_StopsTrafficLightThreads() throws IOException, InterruptedException {
+        intersectionProcess = new IntersectionProcess("Cr1", configFile.toString());
+        intersectionProcess.initialize();
+        
+        Thread serverThread = new Thread(() -> {
+            try {
+                intersectionProcess.start();
+            } catch (IOException e) { }
+        });
+        serverThread.start();
+        
+        Thread.sleep(500);
+        
+        int threadCountBefore = Thread.activeCount();
+        
+        intersectionProcess.shutdown();
+        serverThread.join(2000);
+        
+        Thread.sleep(500); // wait for threads to die
+        
+        // thread count should decrese (traffic light threads stop)
+        int threadCountAfter = Thread.activeCount();
+        assertTrue(threadCountAfter <= threadCountBefore);
+    }
+
+    // integration tests
+
+    @Test
+    @Timeout(15)
+    public void testIntegration_TwoIntersectionsVehicleTransfer() throws IOException, InterruptedException {
+        // setup 2 intersections
+        IntersectionProcess cr1 = new IntersectionProcess("Cr1", configFile.toString());
+        IntersectionProcess cr2 = new IntersectionProcess("Cr2", configFile.toString());
+        
+        cr1.initialize();
+        cr2.initialize();
+        
+        // start both
+        Thread thread1 = new Thread(() -> {
+            try { cr1.start(); } catch (IOException e) { }
+        });
+        
+        Thread thread2 = new Thread(() -> {
+            try { cr2.start(); } catch (IOException e) { }
+        });
+        
+        thread1.start();
+        thread2.start();
+        
+        Thread.sleep(1000); // wait for servers
+        
+        // send vehicle to Cr1 that goes to Cr2
+        java.util.List<String> route = Arrays.asList("Cr1", "Cr2", "S");
+        Vehicle vehicle = new Vehicle("V001", VehicleType.LIGHT, 0.0, route);
+        
+        try (Socket socket = new Socket("localhost", 18001)) {
+            ObjectOutputStream out = new ObjectOutputStream(socket.getOutputStream());
+            
+            TestVehicleMessage message = new TestVehicleMessage("Entry", "Cr1", vehicle);
+            out.writeObject(message);
+            out.flush();
+            
+            Thread.sleep(2000); // time for processing
+        }
+        
+        cr1.shutdown();
+        cr2.shutdown();
+        thread1.join(2000);
+        thread2.join(2000);
+    }
+
+    @Test
+    public void testMain_MissingArguments() {
+        // main needs intersection ID as argument
+        // cant test System.exit easily in modern java
+        assertTrue(true, "Main method expects intersection ID as first argument");
+    }
+
+    // helper class for testing vehicle messages
+    private static class TestVehicleMessage implements sd.protocol.MessageProtocol {
+        private static final long serialVersionUID = 1L;
+        
+        private final String sourceNode;
+        private final String destinationNode;
+        private final Vehicle payload;
+        
+        public TestVehicleMessage(String sourceNode, String destinationNode, Vehicle vehicle) {
+            this.sourceNode = sourceNode;
+            this.destinationNode = destinationNode;
+            this.payload = vehicle;
+        }
+        
+        @Override
+        public MessageType getType() {
+            return MessageType.VEHICLE_TRANSFER;
+        }
+        
+        @Override
+        public Object getPayload() {
+            return payload;
+        }
+        
+        @Override
+        public String getSourceNode() {
+            return sourceNode;
+        }
+        
+        @Override
+        public String getDestinationNode() {
+            return destinationNode;
+        }
+    }
+}