diff --git a/src/main/java/com/fathzer/jchess/uci/UCI.java b/src/main/java/com/fathzer/jchess/uci/UCI.java
index c68eb50..f503025 100644
--- a/src/main/java/com/fathzer/jchess/uci/UCI.java
+++ b/src/main/java/com/fathzer/jchess/uci/UCI.java
@@ -153,6 +153,10 @@ protected void doNewGame(Deque<String> tokens) {
 	}
 
 	protected void doPosition(Deque<String> tokens) {
+		if (tokens.isEmpty()) {
+			debug("missing position definition");
+			return;
+		}
 		final String first = tokens.pop();
 		final String fen;
 		if ("fen".equals(first)) {
diff --git a/src/test/java/com/fathzer/jchess/uci/UCITest.java b/src/test/java/com/fathzer/jchess/uci/UCITest.java
index 55a19bd..98d4e2b 100644
--- a/src/test/java/com/fathzer/jchess/uci/UCITest.java
+++ b/src/test/java/com/fathzer/jchess/uci/UCITest.java
@@ -28,11 +28,11 @@ void clear() {
 
 	@Test
 	void test() {
-//		assertFalse(uci.post("cjhjhl",500));
-//		assertFalse(uci.getDebug().isEmpty());
+		assertFalse(uci.post("cjhjhl",500));
+		assertFalse(uci.getDebug().isEmpty());
 		
 		clear();
 		assertTrue(uci.post("position", 60000));
-		System.out.println(uci.getOutput());
+		assertFalse(uci.getDebug().isEmpty());
 	}
 }
diff --git a/src/test/java/com/fathzer/jchess/uci/util/InstrumentedUCI.java b/src/test/java/com/fathzer/jchess/uci/util/InstrumentedUCI.java
index c782995..cace2f5 100644
--- a/src/test/java/com/fathzer/jchess/uci/util/InstrumentedUCI.java
+++ b/src/test/java/com/fathzer/jchess/uci/util/InstrumentedUCI.java
@@ -22,7 +22,7 @@ private UnknownCommandException(String command) {
 	private final BlockingQueue<String> input;
 	private final BlockingQueue<String> output;
 	private final BlockingQueue<String> debug;
-	private final Map<String, Exception> exceptions;
+	private final Map<String, Throwable> exceptions;
 	
 	public InstrumentedUCI(Engine defaultEngine) {
 		super(defaultEngine);
@@ -47,6 +47,11 @@ protected void out(CharSequence message) {
 		output.add(message.toString());
 	}
 
+	@Override
+	protected void err(String tag, Throwable e) {
+		exceptions.put(tag, e);
+	}
+
 	@Override
 	protected void debug(CharSequence message) {
 		debug.add(message.toString());
@@ -75,7 +80,7 @@ public boolean post(String command, long timeOutMS) {
 		try {
 			synchronized (this) {
 				wait(timeOutMS);
-				final Exception e = exceptions.get(command);
+				final Throwable e = exceptions.get(command);
 				if (e!=null) {
 					if (e instanceof UnknownCommandException) {
 						return false;