String Calculator TDD kata

string-calculator-tdd-cata.scala

import java.util.regex.Pattern

def add(numbers: String, delimiters: Seq[String] = Seq(",")): Int = {
  val delimRegex = "^//(.+?)\n(.*)$".r
  val multiDelim = "^//(\\[.+?\\])\n(.*)$".r
  numbers match {
    case "" => 0
    case multiDelim(dels, ns) => add(ns, dels.init.tail split "\\]\\[")
    case delimRegex(del, ns) => add(ns, Seq(del))
    case ns =>
      val mkDelim = (delimiters :+ "\n") map Pattern.quote mkString ("(", "|", ")")
      val ints = ns split mkDelim map (_.toInt)
      val negs = ints filter (_ < 0)
      if (negs nonEmpty) throw new Exception(negs mkString ",")
      else ints filter (_ <= 1000) sum
  }
}

def tests = Seq[(String, Boolean)](
  "zero"      -> (add("")  == 0),
  "1 num"     -> (add("1") == 1),
  "1 num"     -> (add("0") == 0),
  "1 num"     -> (add("9") == 9),
  "2 nums"    -> (add("1,2") == 3),
  "2 nums"    -> (add("0,0") == 0),
  "2 nums"    -> (add("9,1") == 10),
  "3 nums"    -> (add("1,2,3") == 6),
  "3 nums"    -> (add("0,0,0") == 0),
  "3 nums"    -> (add("9,1,10") == 20),
  "many nums" -> (add("1,1,1,1,1,1,1,1,1,1") == 10),
  "newlines"  -> (add("1\n2") == 3),
  "newlines"  -> (add("1\n2,3") == 6),
  "newlines"  -> (add("1,2\n3") == 6),
  "newlines"  -> (add("1\n2\n3") == 6),
  "delims"    -> (add("//;\n1") == 1),
  "delims"    -> (add("//;\n1;2;3") == 6),
  "delims"    -> (add("//*\n1*2*3") == 6),
  "delims"    -> (add("//.\n1.2.3") == 6),
  "negs"      -> excMsg(add("-1"), "-1"),
  "negs"      -> excMsg(add("-1,1"), "-1"),
  "negs"      -> excMsg(add("-1,-1"), "-1,-1"),
  "bigs"      -> (add("2,1001") == 2),
  "bigs"      -> (add("1001,1001") == 0),
  "longdel"   -> (add("//***\n1***2***3") == 6),
  "longdel"   -> (add("//***\n1") == 1),
  "longdel"   -> (add("//***\n") == 0),
  "muldel"    -> (add("//[*]\n1*2") == 3),
  "muldel"    -> (add("//[*][%]\n1*2%3") == 6),
  "muldel"    -> (add("//[*][%]\n") == 0),
  "lmuldel"   -> (add("//[***][%]\n1***2%3***4") == 10),
  ""          -> true
)

def tee[T](a: T) = {println(a); a }

def excMsg(comp: => Any, msg: String): Boolean =
  try { 
    comp; false 
  } catch { 
    case e => e.getMessage == msg
  }

tests foreach {
  case (name, false) => println("failed! "+name)
  case (name, true)  => println("ok      "+name)
}