TestSolution fix: default 1 objective with value 0

common/src/main/java/es/urjc/etsii/grafo/testutil/TestSolution.java

@@ -22,7 +22,7 @@ public static TestSolution[] from(TestInstance instance, double... scores) {
         return solutions;
     }
 
-    protected double[] score;
+    protected double[] score = new double[1];
 
     Map<String, Function<TestSolution, Object>> properties = new HashMap<>();