fix en passant

app/src/main/java/chess/model/Move.java

@@ -30,7 +30,7 @@ public class Move {
 		int diffY = getFinish().getY() - getStart().getY();
 
 		assert Math.abs(diffX) < Coordinate.VALUE_MAX : "Move is too big!";
-		assert Math.abs(diffX) < Coordinate.VALUE_MAX : "Move is too big!";
+		assert Math.abs(diffY) < Coordinate.VALUE_MAX : "Move is too big!";
 
 		if (diffX == 0)
 			return Math.abs(diffY);
@@ -53,4 +53,11 @@ public class Move {
 		return deadPieceCoords;
 	}
 
+	@Override
+	public boolean equals(Object obj) {
+		if (obj instanceof Move other)
+			return this.start.equals(other.start) && this.finish.equals(other.finish);
+		return false;
+	}
+
 }