Runs DS enabled loop in process (#785)

Solves mutex issues, and other issues with the existing teststand
software. And simplifies the unit test structure.

wpilibjIntegrationTests/src/main/java/edu/wpi/first/wpilibj/MockDS.java

@@ -0,0 +1,85 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2017 FIRST. All Rights Reserved.                             */
+/* Open Source Software - may be modified and shared by FRC teams. The code   */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project.                                                               */
+/*----------------------------------------------------------------------------*/
+
+package edu.wpi.first.wpilibj;
+
+import java.io.IOException;
+import java.net.DatagramPacket;
+import java.net.DatagramSocket;
+import java.net.InetSocketAddress;
+import java.net.SocketException;
+
+public class MockDS {
+  private Thread m_thread;
+
+  private void generateEnabledDsPacket(byte[] data, short sendCount) {
+    data[0] = (byte) (sendCount >> 8);
+    data[1] = (byte) sendCount;
+    data[2] = 0x01; // general data tag
+    data[3] = 0x04; // teleop enabled
+    data[4] = 0x10; // normal data request
+    data[5] = 0x00; // red 1 station
+  }
+
+  @SuppressWarnings("JavadocMethod")
+  public void start() {
+
+    m_thread = new Thread(() -> {
+      DatagramSocket socket;
+      try {
+        socket = new DatagramSocket();
+      } catch (SocketException e1) {
+        // TODO Auto-generated catch block
+        e1.printStackTrace();
+        return;
+      }
+      InetSocketAddress addr = new InetSocketAddress("127.0.0.1", 1110);
+      byte[] sendData = new byte[6];
+      DatagramPacket packet = new DatagramPacket(sendData, 0, 6, addr);
+      short sendCount = 0;
+      int initCount = 0;
+      while (!Thread.currentThread().isInterrupted()) {
+        try {
+          Thread.sleep(20);
+          generateEnabledDsPacket(sendData, sendCount++);
+          // ~50 disabled packets are required to make the robot actually enable
+          // 1 is definitely not enough.
+          if (initCount < 50) {
+            initCount++;
+            sendData[3] = 0;
+          }
+          packet.setData(sendData);
+          socket.send(packet);
+        } catch (InterruptedException ex) {
+          Thread.currentThread().interrupt();
+        } catch (IOException ex) {
+          // TODO Auto-generated catch block
+          ex.printStackTrace();
+        }
+      }
+      socket.close();
+    });
+    // Because of the test setup in Java, this thread will not be stopped
+    // So it must be a daemon thread
+    m_thread.setDaemon(true);
+    m_thread.start();
+  }
+
+  @SuppressWarnings("JavadocMethod")
+  public void stop() {
+    if (m_thread == null) {
+      return;
+    }
+    m_thread.interrupt();
+    try {
+      m_thread.join(1000);
+    } catch (InterruptedException ex) {
+      // TODO Auto-generated catch block
+      ex.printStackTrace();
+    }
+  }
+}

wpilibjIntegrationTests/src/main/java/edu/wpi/first/wpilibj/test/AbstractComsSetup.java

@@ -17,6 +17,7 @@ import java.util.logging.Level;
 import java.util.logging.Logger;
 
 import edu.wpi.first.wpilibj.DriverStation;
+import edu.wpi.first.wpilibj.MockDS;
 import edu.wpi.first.wpilibj.RobotBase;
 import edu.wpi.first.wpilibj.Timer;
 import edu.wpi.first.wpilibj.hal.HAL;
@@ -34,6 +35,9 @@ public abstract class AbstractComsSetup {
    */
   private static boolean initialized = false;
 
+  // We have no way to stop the MockDS, so its thread is daemon.
+  private static  MockDS ds;
+
   /**
    * This sets up the network communications library to enable the driver
    * station. After starting network coms, it will loop until the driver station
@@ -45,6 +49,10 @@ public abstract class AbstractComsSetup {
       // Set some implementations so that the static methods work properly
       RobotBase.initializeHardwareConfiguration();
       HAL.observeUserProgramStarting();
+      DriverStation.getInstance().getAlliance();
+
+      ds = new MockDS();
+      ds.start();
 
       LiveWindow.setEnabled(false);
       TestBench.out().println("Started coms");
@@ -57,8 +65,7 @@ public abstract class AbstractComsSetup {
         } catch (InterruptedException ex) {
           ex.printStackTrace();
         }
-        // Prints the message on one line overwriting itself each time
-        TestBench.out().print("\rWaiting for enable: " + enableCounter++);
+        TestBench.out().println("Waiting for enable: " + enableCounter++);
       }
       TestBench.out().println();