import { describe, expect, test } from "bun:test"

import { lazy } from "../../src/util/lazy"

describe("util.lazy", () => {

test("should call function only once", () => {

let callCount = 0

const getValue = () => {

callCount++

return "expensive value"

}

const lazyValue = lazy(getValue)

expect(callCount).toBe(0)

const result1 = lazyValue()

expect(result1).toBe("expensive value")

expect(callCount).toBe(1)

const result2 = lazyValue()

expect(result2).toBe("expensive value")

expect(callCount).toBe(1)

})

test("should preserve the same reference", () => {

const obj = { value: 42 }

const lazyObj = lazy(() => obj)

const result1 = lazyObj()

const result2 = lazyObj()

expect(result1).toBe(obj)

expect(result2).toBe(obj)

expect(result1).toBe(result2)

})

test("should work with different return types", () => {

const lazyString = lazy(() => "string")

const lazyNumber = lazy(() => 123)

const lazyBoolean = lazy(() => true)

const lazyNull = lazy(() => null)

const lazyUndefined = lazy(() => undefined)

expect(lazyString()).toBe("string")

expect(lazyNumber()).toBe(123)

expect(lazyBoolean()).toBe(true)

expect(lazyNull()).toBe(null)

expect(lazyUndefined()).toBe(undefined)

})

})