assertEquals("(2 - 3)" , ctx.mapFunction("-","2","3"));
assertEquals("(2 * 3 * 4)" , ctx.mapFunction("*","2","3","4"));
assertEquals("(2 / 4)" , ctx.mapFunction("/","2","4"));
assertEquals("(Math.min(2,Math.min(3,4)))" , ctx.mapFunction("min","2","3","4"));
assertEquals("(Math.max(2,Math.max(3,4)))" , ctx.mapFunction("max","2","3","4"));
assertEquals("(2 + 3 + 4)" , ctx.mapFunction("sum","2","3","4"));
assertEquals("(2 * 3 * 4)" , ctx.mapFunction("product","2","3","4"));
assertEquals("((2 + 3 + 4) / 3)" , ctx.mapFunction("avg","2","3","4"));
assertEquals("(3)" , ctx.mapFunction("median","1","2","3","4","5"));
assertEquals("( 0.5 * 3 + 0.5 * 4 )" , ctx.mapFunction("median","1","2","3","4","5","6"));