<!--
title: Stable test assertions
domain: observability
topic: Testing
language: TypeScript
source: grafana/grafana
updated: 2025-07-03
url: https://awesomereviewers.com/reviewers/grafana-stable-test-assertions/
-->

Write tests that focus on behavior rather than implementation details to create more stable and maintainable test suites. Avoid using arbitrary timeouts and assertions that frequently break with implementation changes.

**Instead of using arbitrary timeouts:**
```typescript
// Avoid this:
await searchInput.click();
await page.keyboard.type('Datasource tests - MySQL');
await page.waitForTimeout(300); // Brittle: might be too short or too long

// Prefer this:
await searchInput.click();
await page.keyboard.type('Datasource tests - MySQL');
await expect(rowGroup).toHaveCount(1); // Will auto-retry until condition is met
await expect(rows).toHaveCount(expectedLength);
```

**Instead of asserting implementation details:**
```typescript
// Avoid this:
expect(scene.state.$behaviors).toHaveLength(6); // Brittle: breaks when behavior count changes

// Prefer this:
expect(scene.state.$behaviors.find(b => b instanceof CursorSyncBehavior)).toBeDefined(); // Tests actual functionality
```

By focusing tests on behavior and using the testing framework's built-in retry and assertion mechanisms, you'll create more reliable tests that require less maintenance as your codebase evolves.