Phase 1: 共用类型定义 - apps/server/src/common/import-result.types.ts — ImportRowError + ImportResult<T> - apps/admin/src/types/import.ts — 前端对应类型 + ImportDisplayConfig Phase 2: 后端增强 - students.service.ts — batchImport/matchImport 改为 ImportResult 格式 · 每行跳过时收集 ImportRowError(code + reason) · reason 支持 markdown 标记(**字段名** / `值`) - archive.service.ts — batchImportArchive 统一用 ImportResult 格式 · 各 Sheet 错误使用标准 error code - archive.controller.ts — 日志使用新的 success 字段 Phase 3: 前端基础 - 安装 react-markdown - ImportResultModal 组件(共用导入结果弹窗) · Statistic 成功统计 + Table 错误明细 · 原因列支持 react-markdown 渲染(粗体字段名、等宽代码值) · 错误类型用 Tag 颜色区分 - api/index.ts — 403 错误从 console.warn 改为 message.warning 用户可见 Phase 4: 前端集成 - Students/index.tsx — 替换硬编码导入结果弹窗 · 删除'后端只返回统计汇总'注释和跳过原因 hardcode · 新格式自动使用 ImportResultModal,旧格式兼容 - StudentProfileContent/index.tsx — 替换内联导入 Modal 为 ImportResultModal
3.4 KiB
Condition-Based Waiting
Overview
Flaky tests often guess at timing with arbitrary delays. This creates race conditions where tests pass on fast machines but fail under load or in CI.
Core principle: Wait for the actual condition you care about, not a guess about how long it takes.
When to Use
digraph when_to_use {
"Test uses setTimeout/sleep?" [shape=diamond];
"Testing timing behavior?" [shape=diamond];
"Document WHY timeout needed" [shape=box];
"Use condition-based waiting" [shape=box];
"Test uses setTimeout/sleep?" -> "Testing timing behavior?" [label="yes"];
"Testing timing behavior?" -> "Document WHY timeout needed" [label="yes"];
"Testing timing behavior?" -> "Use condition-based waiting" [label="no"];
}
Use when:
- Tests have arbitrary delays (
setTimeout,sleep,time.sleep()) - Tests are flaky (pass sometimes, fail under load)
- Tests timeout when run in parallel
- Waiting for async operations to complete
Don't use when:
- Testing actual timing behavior (debounce, throttle intervals)
- Always document WHY if using arbitrary timeout
Core Pattern
// ❌ BEFORE: Guessing at timing
await new Promise(r => setTimeout(r, 50));
const result = getResult();
expect(result).toBeDefined();
// ✅ AFTER: Waiting for condition
await waitFor(() => getResult() !== undefined);
const result = getResult();
expect(result).toBeDefined();
Quick Patterns
| Scenario | Pattern |
|---|---|
| Wait for event | waitFor(() => events.find(e => e.type === 'DONE')) |
| Wait for state | waitFor(() => machine.state === 'ready') |
| Wait for count | waitFor(() => items.length >= 5) |
| Wait for file | waitFor(() => fs.existsSync(path)) |
| Complex condition | waitFor(() => obj.ready && obj.value > 10) |
Implementation
Generic polling function:
async function waitFor<T>(
condition: () => T | undefined | null | false,
description: string,
timeoutMs = 5000
): Promise<T> {
const startTime = Date.now();
while (true) {
const result = condition();
if (result) return result;
if (Date.now() - startTime > timeoutMs) {
throw new Error(`Timeout waiting for ${description} after ${timeoutMs}ms`);
}
await new Promise(r => setTimeout(r, 10)); // Poll every 10ms
}
}
See condition-based-waiting-example.ts in this directory for complete implementation with domain-specific helpers (waitForEvent, waitForEventCount, waitForEventMatch) from actual debugging session.
Common Mistakes
❌ Polling too fast: setTimeout(check, 1) - wastes CPU
✅ Fix: Poll every 10ms
❌ No timeout: Loop forever if condition never met ✅ Fix: Always include timeout with clear error
❌ Stale data: Cache state before loop ✅ Fix: Call getter inside loop for fresh data
When Arbitrary Timeout IS Correct
// Tool ticks every 100ms - need 2 ticks to verify partial output
await waitForEvent(manager, 'TOOL_STARTED'); // First: wait for condition
await new Promise(r => setTimeout(r, 200)); // Then: wait for timed behavior
// 200ms = 2 ticks at 100ms intervals - documented and justified
Requirements:
- First wait for triggering condition
- Based on known timing (not guessing)
- Comment explaining WHY
Real-World Impact
From debugging session (2025-10-03):
- Fixed 15 flaky tests across 3 files
- Pass rate: 60% → 100%
- Execution time: 40% faster
- No more race conditions