### Question:
ArrayIndexExpr extends Expr { @Override public int getNumChildren() { return 2; } ArrayIndexExpr(Expr array, Expr index); Expr getArray(); Expr getIndex(); void setIndex(Expr index); @Override void accept(IAstVisitor visitor); @Override ArrayIndexExpr clone(); @Override boolean hasChild(IAstNode candidateChild); @Override Expr getChild(int index); @Override void setChild(int index, Expr expr); @Override int getNumChildren();  }### Answer:
@Test public void getNumChildren() throws Exception { assertEquals(2, expr.getNumChildren()); }