Testdriver:making Assertions Agent Skill
Locate elements and verify app state with AI-powered assertions
Install
one command, takes just this skill from the repositorynpx skills add https://github.com/testdriverai/testdriverai --skill testdriver:making-assertionsThe instruction itself
6 sections, as written by the author<!-- Generated from making-assertions.mdx. DO NOT EDIT. -->
Once a test runs, validate that the app did what it should. Validation has two parts: locating the elements you want to check, and making assertions about the state of your app. TestDriver uses AI as a judge, returning a boolean plus reasoning about whether your app is in the expected state.
Locating Elements
Locating Single Elements
Use natural language to describe elements. Descriptions should be specific enough to locate the element, but not too-specific that they break with minor UI changes. For example:
await testdriver.find('email input field');
await testdriver.find('first product card in the grid');
await testdriver.find('dropdown menu labeled "Country"');
<Info>TestDriver will cache found elements for improved performance on subsequent calls. Learn more about element caching here.</Info>
Debugging Found Elements
After finding an element, you can inspect its properties for debugging:
const button = await testdriver.find('submit button');
console.log(button);
This outputs all element properties:
{
description: 'submit button',
found: true,
x: 150,
y: 300,
coordinates: { x: 150, y: 300, centerX: 200, centerY: 320 },
threshold: 0.8,
confidence: 0.95,
similarity: 0.92,
selector: 'button[type="submit"]',
cache: {
hit: true,
strategy: 'pixel-diff',
createdAt: '2025-01-15T10:30:00Z',
diffPercent: 0.02,
imageUrl: 'https://...'
}
}
Working with Multiple Elements
Find and interact with multiple elements:
// Find all matching elements
const products = await testdriver.findAll('product card');
console.log(`Found ${products.length} products`);
// Interact with each
for (const product of products) {
const title = await product.find('title text');
console.log('Product:', title.text);
await product.find('add to cart button').click();
}
// Or find specific element
const firstProduct = products[0];
await firstProduct.click();
Making Assertions
Use AI-powered assertions to verify application state. TestDriver acts as a judge: it evaluates your natural-language statement against the current state of the app and returns a boolean plus reasoning explaining the verdict.
// Verify visibility
await testdriver.assert('login page is displayed');
await testdriver.assert('submit button is visible');
await testdriver.assert('loading spinner is not visible');
// Verify content
await testdriver.assert('page title is "Welcome"');
await testdriver.assert('success message says "Account created"');
await testdriver.assert('error message contains "Invalid email"');
// Verify state
await testdriver.assert('checkbox is checked');
await testdriver.assert('dropdown shows "United States"');
await testdriver.assert('button is disabled');
// Verify visual appearance
await testdriver.assert('submit button is blue');
await testdriver.assert('form has red border');
<Info>Assertions are not cached and always re-evaluated to ensure accuracy.</Info>
Next
<Card title="Adapt" icon="arrows-rotate" href="/v7/performing-actions">
Drive your app forward by performing actions on the elements you've located and validated.
</Card>
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How to use it
Take testdriverai/testdriver:making-assertions from the repository into ~/.claude/skills for personal
use, or into .claude/skills inside a project.
The agent identifies a skill by the name field in its header. Two skills with the
same name cannot sit side by side — one of them will be ignored.