问编译错误:错误:对象scalatest不是package.org的成员，我没有使用sbt

EN

  /** Calculate factorial of n
    * Pre: n >= 0
    * Post: returns n! */
  def fact(n: Int) : BigInt = {
    require(n>=0)
    if(n==0) 1 else fact(n-1)*n
  }

  // Main method
  def main(args: Array[String]) : Unit = { 
    print("Please input a number: ")
    val n = scala.io.StdIn.readInt()
    if(n>=0){
      val f = fact(n)
      println("The factorial of "+n+" is "+f)
    }
    else println("Sorry, negative numbers aren't allowed")
  }
}

import org.scalatest.funsuite.AnyFunSuite

import Factorial.fact

class FactTest extends AnyFunSuite {
   test("0! is 1"){ assert(fact(0) === 1) }
   test("5! is 120") { assert(fact(5) === 120) }
   test("3! is 5") {assert(fact(3) === 5) } //Want to see what happens when the test isn't passed
}