nim-codex/tests/codex/utils/testoptions.nim

import std/unittest
import codex/utils/options
import ../helpers

checksuite "optional casts":
  test "casting value to same type works":
    check 42 as int == some 42

  test "casting value to unrelated type evaluates to None":
    check 42 as string == string.none

  test "casting value to subtype works":
    type
      BaseType = ref object of RootObj
      SubType = ref object of BaseType
    let x: BaseType = SubType()
    check x as SubType == SubType(x).some

  test "casting to unrelated subtype evaluates to None":
    type
      BaseType = ref object of RootObj
      SubType = ref object of BaseType
      OtherType = ref object of BaseType
    let x: BaseType = SubType()
    check x as OtherType == OtherType.none

  test "casting works on optional types":
    check 42.some as int == some 42
    check 42.some as string == string.none
    check int.none as int == int.none

checksuite "Optionalize":
  test "does not except non-object types":
    static:
      doAssert not compiles(Optionalize(int))

  test "converts object fields to option":
    type BaseType = object
      a: int
      b: bool
      c: string
      d: Option[string]

    type OptionalizedType = Optionalize(BaseType)

    check OptionalizedType.a is Option[int]
    check OptionalizedType.b is Option[bool]
    check OptionalizedType.c is Option[string]
    check OptionalizedType.d is Option[string]