### Question:
CategoricalDecision extends Decision { @Override public String toString() { StringBuilder result = new StringBuilder(); result.append("(#").append(getFeatureNumber()).append(" ∈ ["); int category = -1; boolean first = true; while ((category = activeCategoryEncodings.nextSetBit(category + 1)) >= 0) { if (first) { first = false; } else { result.append(','); } result.append(category); } result.append("])"); return result.toString(); } CategoricalDecision(int featureNumber,
                             BitSet activeCategoryEncodings,
                             boolean defaultDecision); @Override boolean getDefaultDecision(); BitSet getActiveCategoryEncodings(); @Override boolean isPositive(Example example); @Override FeatureType getType(); @Override boolean equals(Object o); @Override int hashCode(); @Override String toString();  }### Answer:
@Test public void testToString() { BitSet activeCategories = new BitSet(10); activeCategories.set(2); activeCategories.set(5); CategoricalDecision decision = new CategoricalDecision(0, activeCategories, true); assertEquals("(#0 ∈ [2,5])", decision.toString()); }