Java client BECN implementation (#155)

TestScripts/Java Tests/XPlaneDiscoveryTests.java

@@ -0,0 +1,73 @@
+package gov.nasa.xpc.test;
+
+import static org.junit.Assert.*;
+
+import gov.nasa.xpc.discovery.Beacon;
+import gov.nasa.xpc.discovery.BeaconParser;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.io.IOException;
+import java.net.DatagramPacket;
+
+
+public class XPlaneDiscoveryTests {
+
+    private BeaconParser parser;
+    private DatagramPacket packet;
+
+    @Before
+    public void setup() {
+        parser = new BeaconParser();
+        byte[] bytes = HexHelper.decodeHexString("4245434E0071BFFC2B0000312E332D72632E310000000000000000");
+        packet = new DatagramPacket(bytes, 0, bytes.length);
+    }
+
+    @Test
+    public void readBeaconParsesPort() throws IOException {
+        Beacon beacon = parser.readBCN(packet);
+        assertEquals(beacon.getPluginPort(), 49009);
+    }
+
+    @Test
+    public void readBeaconParsesXplaneVersion() throws IOException {
+        Beacon beacon = parser.readBCN(packet);
+        assertEquals(beacon.getXplaneVersion(), "112.60");
+
+    }
+
+    @Test
+    public void readBeaconParsesPluginVersion() throws IOException {
+        Beacon beacon = parser.readBCN(packet);
+        assertEquals(beacon.getPluginVersion(), "1.3-rc.1");
+    }
+}
+
+class HexHelper {
+    static byte[] decodeHexString(String hexString) {
+        if (hexString.length() % 2 == 1) {
+            throw new IllegalArgumentException("Invalid hexadecimal String supplied.");
+        }
+
+        byte[] bytes = new byte[hexString.length() / 2];
+        for (int i = 0; i < hexString.length(); i += 2) {
+            bytes[i / 2] = hexToByte(hexString.substring(i, i + 2));
+        }
+        return bytes;
+    }
+
+    private static byte hexToByte(String hexString) {
+        int firstDigit = toDigit(hexString.charAt(0));
+        int secondDigit = toDigit(hexString.charAt(1));
+        return (byte) ((firstDigit << 4) + secondDigit);
+    }
+
+    private static int toDigit(char hexChar) {
+        int digit = Character.digit(hexChar, 16);
+        if (digit == -1) {
+            throw new IllegalArgumentException(
+                    "Invalid Hexadecimal Character: " + hexChar);
+        }
+        return digit;
+    }
+}