Flaky test

<div class="stage"><div class="title">FLAKY TEST</div><div class="canvas"><div class="runs" id="runs"></div><div class="race"><div class="ready" id="ready"></div><div class="assert" id="assert"></div></div><div class="reason" id="reason">assertion ran before ready</div></div></div>

.stage{width:min(94vw,820px);height:min(88vh,330px);box-sizing:border-box;padding:clamp(9px,2.4vmin,18px);border:1px solid var(--line);border-radius:13px;background:var(--surface);display:flex;flex-direction:column;gap:clamp(7px,2vmin,14px);font:600 clamp(12px,2.5vmin,16px)/1.28 "Pretendard Variable",Pretendard,-apple-system,BlinkMacSystemFont,"Apple SD Gothic Neo",sans-serif;color:var(--fg);overflow:hidden}.title{color:var(--accent);letter-spacing:.035em;flex:none}.canvas{position:relative;flex:1;min-height:0;display:flex;align-items:center;justify-content:center}.muted{color:var(--muted)}.mono{font-family:ui-monospace,SFMono-Regular,monospace}.box{border:1px solid var(--line);border-radius:8px;background:var(--bg);padding:clamp(5px,1.4vmin,12px);text-align:center}.active{border-color:var(--accent)!important;color:var(--accent)!important;background:color-mix(in srgb,var(--accent) 12%,var(--surface))!important}.canvas{flex-direction:column;gap:clamp(10px,3vmin,22px)}.runs{display:flex;gap:5px;justify-content:center}.runs span{width:clamp(20px,5vmin,32px);height:clamp(20px,5vmin,32px);display:grid;place-items:center;border-radius:4px;border:1px solid var(--line)}.runs .pass{color:var(--accent);border-color:var(--accent)}.runs .fail{color:var(--accent-3);border-color:var(--accent-3)}.race{position:relative;width:min(90%,460px);height:30px;border-top:2px solid var(--line)}.ready,.assert{position:absolute;top:-8px;width:15px;height:15px;border-radius:50%;background:var(--accent);transition:left .5s}.ready{left:67%}.assert{left:32%;background:var(--accent-3)}.reason{color:var(--muted);text-align:center}

let n=0;const marks=[];function run(){const pass=n++%3===2;marks.push(pass?'PASS':'FAIL');if(marks.length>7)marks.shift();document.getElementById('runs').innerHTML=marks.map(x=>'<span class='+ (x==='PASS'?'pass':'fail') +'>'+ (x==='PASS'?'✓':'×') +'</span>').join('');document.getElementById('assert').style.left=pass?'82%':'32%';document.getElementById('reason').textContent=pass?'assertion waited for ready':'assertion ran before ready'}run();setInterval(run,1000)