Assertions & Validation

Assertions verify that your application behaves correctly after performing actions. In KaneAI, you write assertions in natural language, and the AI evaluates them against the current page state. This guide covers every assertion type, shows how to write them reliably, and explains how to handle tricky validation scenarios.

note

All assertions have an option for failure behavior. By default, a failure in assertion will fail the test during execution. You can configure the default failure behavior for assertions via Organisation Settings. See more details in Failure Conditions.

Assertion Categories

Text Assertions

Check whether specific text content is present (or absent) on the page.

assert "Welcome Back, John!" is visible
assert "Your order has been placed" is displayed
assert error message "Invalid email address" is visible
assert "Out of Stock" is not visible on the page

With variables:

assert {{username}} is visible on the page
assert {{api_response.message}} contains "success"

Visual Assertions

Verify that images, logos, icons, or visual elements appear correctly.

assert the TestMu logo is visible in the header
assert the product image is displayed
assert the green checkmark icon appears next to "Verified"

warning

Visual assertions rely on screenshots. Elements smaller than 12×12 pixels may not be detected reliably. Avoid asserting on exact hex colors — use descriptive colors instead.

URL & Browser State Assertions

Validate the browser state such as the current URL or page title.

assert the current URL is "https://example.com/dashboard"
assert the current URL contains "/dashboard"
assert the page title contains "Dashboard"

Relative/Layout Assertions

Check the spatial relationship between elements.

assert the "Login" button is in the same row as the "Register" link
assert the "Submit" button is below the form fields

Mathematical Assertions

Validate calculations and numeric values.

assert 3 + 4 = 7
assert the cart total equals the sum of item prices visible

Writing Good Assertions: Do's and Don'ts

Good Assertion	Bad Assertion	Why
assert text "Submit" on the form footer is visible	assert that the submit button works and the layout is correct	Combines multiple concerns; "works" is vague
assert the textbox contains the exact value "heading1"	assert the textbox has heading	"heading" is ambiguous — which heading?
assert the TestMu logo is visible	assert 3 search results are shown (as a visual assertion)	Count assertions need text-based evidence, not visual
assert "Error" is not visible on the page	assert there are no errors	Too vague; specify what kind of error

Key Rules for Reliable Assertions

Be Specific, Not Subjective

The assertion must have a clear true/false answer given the page state.

Bad

assert the page is user-friendly
assert the layout is correct

Good

assert the navigation menu has 5 items
assert the "Search" input field is visible at the top of the page

Avoid Asserting on Imperceivable Details

KaneAI uses a screenshot + DOM combination. Very small visual details may not be detectable.

Risky assertions (may be flaky):

• Exact hex color codes (#ff5733)
• Colors of thin lines or indicator dots
• SVG shapes smaller than 12px
• Font sizes or font families

Safer alternatives:

assert the button appears red          (instead of assert color is #ff0000)
assert the error border is visible   (instead of assert border is 2px solid red)

Real-World Assertion Scenarios

Scenario: Login Flow Validation

type "[email protected]" in the email field
type "wrong_password" in the password field
click on "Sign In" button
assert "Invalid credentials" error message is visible

clear the password field
type "CorrectPass123" in the password field
click on "Sign In" button
assert the current URL contains "/dashboard"
assert "Welcome, Admin" is visible

Scenario: E-Commerce Cart Validation

click "Add to Cart" for the "Wireless Mouse" product
click on the cart icon
assert "Wireless Mouse" is visible in the cart
assert the cart item count shows "1"
assert the cart total is "$29.99"
click "Remove" next to "Wireless Mouse"
assert "Your cart is empty" is visible

Scenario: Form Validation Messages

click the "Submit" button without filling any fields
assert "First name is required" error is visible
assert "Email is required" error is visible
assert "Password is required" error is visible

type "J" in the "First Name" field
assert "First name must be at least 2 characters" is visible

Scenario: Search Results Verification

type "laptop" in the search field and press Enter
wait for 3 seconds
assert search results are visible
assert the first result contains the word "laptop"
assert the results count is greater than 0

Scenario: Data Table Content Validation

assert the "Users" table header is visible
assert the table contains a row with "[email protected]"
assert "Active" status is shown next to "[email protected]"

Asserting with Variables

Variables make assertions dynamic and reusable, especially when combined with API responses or stored values.

String Variable Assertions

set expectedTitle as "Dashboard"
assert {{expectedTitle}} is visible on the page

JSON Variable Assertions (from API)

After making an API call via the / command, the response is stored as a JSON variable:

assert {{api_response.status}} is "200"
assert {{api_response.data.email}} is "[email protected]"
assert {{api_response.data.items}} contains "Laptop"

Cross-Referencing UI and API Data

Store a value from the UI, make an API call, and compare:

Fetch the order ID displayed on the confirmation page
-- (stored as a variable such as {{orderID}}) --
-- Make API call to verify order via /api command --
assert {{api_response.orderId}} equals {{orderID}}

Conditional Assertions

KaneAI supports basic if-else logic for assertions that depend on page state.

if "Login" button is visible then click on it
if price < 200 then click "Add to Cart" else select the second product

note

Nested conditions are not yet supported. Keep conditional logic simple and flat. For complex branching, break the test into separate test cases.

Unsupported Assertions (Current Limitations)

These assertion types are not yet available via natural language. Use JS snippets as workarounds where applicable.

Category	Example	Workaround
Element State (disabled/enabled)	assert the submit button is disabled	JS: document.querySelector('button[type="submit"]').disabled
CSS Properties	assert font size is 16px	JS: getComputedStyle(element).fontSize
Specific DOM Position	assert the 5th table column contains "Jordan"	JS: document.querySelectorAll('td')[4].textContent
Action-Based	assert tooltip appears after hover	Split into: hover step → wait → assert tooltip text
Nested Conditions	assert A is true AND B is visible	Split into two separate assertions
Changes Over Time	assert the spinner disappears after 5 seconds	Use wait step, then assert spinner is not visible

JS Snippet Workaround: Assert CSS Property

const element = document.querySelector('.price-tag');
const fontSize = getComputedStyle(element).fontSize;
if (fontSize === '16px') {
  return 'PASS: Font size is 16px';
} else {
  throw new Error('FAIL: Font size is ' + fontSize);
}

info

For the full list of JS execution options, see JS Snippets guide.

Configuring Assertion Failure Behavior

By default, assertions fail the test immediately (unless configured otherwise in Organisation Settings). You can configure this per step:

Mode	Behavior
Fail Immediately (default)	Test stops at the failed assertion
Fail and Continue	Assertion failure is recorded, but subsequent steps continue executing
Warn and Continue	Assertion failure is logged as a warning; test is not marked as failed

Configure via: Step menu → Failure Condition → Select behavior.

This is useful when you want to run all assertions in a test and see a complete report of what passed and what failed, rather than stopping at the first failure.