### Question:
UnionBlock implements Block { @Override public String toString() { StringBuilder builder = new StringBuilder(); for (Block block : blocks) { if (builder.length() > 0) { builder.append(" UNION "); } builder.append(block.toString()); } return builder.toString(); } UnionBlock(List<Block> blocks); @Override Predicate not(); @Override @SuppressWarnings("unchecked") R accept(Visitor<R, C> v, C context); @Override Class<? extends Boolean> getType(); static long getSerialversionuid(); List<Block> getBlocks(); @Override BooleanExpression exists(); @Override int hashCode(); @Override boolean equals(Object o); @Override String toString();  }### Answer:
@Test public void To_String() { Block block = Blocks.union(Blocks.S_FIRST, Blocks.S_REST); assertEquals( "{s} http: "UNION " + "{s} http: block.toString()); }