notes/pl/scala/tools/quality/test/scalatest/scalactic.txt

Nice equality

import org.scalactic._
import TripleEquals._
import StringNormalizations._
import Explicitly._

("Hello" === "hello") (after being lowerCased) // true

Normalization

import NormMethods._

implicit val strNormalization = lowerCased // !!! .toEquality

"WHISPER".norm               // "whisper"
"WHISPER".norm === "whisper" // true

Implicit string equality

implicit val strEquality = decided by defaultEquality[String] afterBeing lowerCased

"Hello" === "hello"           // true
"normalized" === "NORMALIZED" // true

Tolerance

import Tolerance._

2.00001 === 2.0 +- 0.01

import TolerantNumerics._

implicit val dblEquality = tolerantDoubleEquality(0.01)

2.00001 === 2.0

Type checked ===

import TypeCheckedTripleEquals._

Some("hi") === "hi"
error: types Some[String] and String do not adhere to the type constraints
selected for the === and !== operators; the missing implicit parameter is
of type org.scalactic.Constraint[Some[String], String]
          Some("hi") === "hi"
                     ^

Or and Every

case class Person(name: String, age: Int)

def parseName(input: String): String Or One[ErrorMessage] = {
    val trimmed = input.trim
    if (!trimmed.isEmpty)
        Good(trimmed)
    else
        Bad(One(s"""${input} is not a valid name"""))
}

def parsePerson(inputName: String, inputAge: String): Person Or Every[ErrorMessage] = {
    val name = parseName(inputName)
    val age = parseAge(inputAge)
    withGood(name, age) { Person(_, _) }
}

parsePerson("Bridget Jones", "29")
// Result: Good(Person(Bridget Jones, 29))

parsePerson("Bridget Jones", "")
// Result: Bad(One("" is not a valid integer))

parsePerson("Bridget Jones", "-29")
// Result: Bad(One("-29" is not a valid integer))

parsePerson("", "")
// Result: Bad(Manye("" is not a valid name, "" is not a valid integer))


Snapshots - easy logging

val a = 1
val b = '2'
val c = "3"

snap(a, b, c) // Result: a was 1, b was '2', c was "3"