Testing Basics

Boolean Assertion

Some tests verify that a condition is true instead of comparing two numbers.

Check a predicate

score
boolean_assertion.swift
Replay: real traced execution (multi-file project)
let score = 82
let passed = score >= 60
let message = passed ? "passing score" : "failing score"

print(message)

let score = 59
let passed = score >= 60
let message = passed ? "passing score" : "failing score"

print(message)

let score = 100
let passed = score >= 60
let message = passed ? "passing score" : "failing score"

print(message)

  1. score ← 82, passed ← true, message ← passing score

    1let score→ 82 = 82  //@score=59, 1002let passed→ true = score82 >= 603let message→ passing score = passedtrue ? "passing score" : "failing score"45print(messagepassing score)
    outputpassing score

  1. score ← 59, passed ← false, message ← failing score

    1let score→ 59 = 592let passed→ false = score59 >= 603let message→ failing score = passedfalse ? "passing score" : "failing score"45print(messagefailing score)
    outputfailing score

  1. score ← 100, passed ← true, message ← passing score

    1let score→ 100 = 1002let passed→ true = score100 >= 603let message→ passing score = passedtrue ? "passing score" : "failing score"45print(messagepassing score)
    outputpassing score
boolean assertion Boolean assertions name the condition being checked and report the result.