Clipboard Assertions

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Clipboard assertions let you verify what a “Copy” button actually copied, extract copied values into variables, and confirm clipboard state after your test writes or clears it.

The Test Clipboard

Every run uses an isolated test clipboard:

Your real clipboard is safe: the OS clipboard is never read and never written. Tests can’t leak your copied data into results, and nothing you copy mid-run interferes with the test
Automatic capture: when the page copies something (a Copy button, Ctrl/Cmd+C on a selection), it lands in the test clipboard
One current entry: like a real clipboard, every copy or clipboard write replaces the previous content
Multi-format: a single entry can carry plain text, HTML, and an image together (e.g. a “Copy image” button)
Same behavior everywhere: headless, headed, and CI runs all behave identically

Planning for Multi-Step Tests

Because the clipboard holds one entry at a time:

Verify a copied value immediately after the copy or write that produced it. A later clipboard write/clear replaces it
To check several copies, interleave: copy A → verify → copy B → verify

What You Can Query

Query	Description
text content	The plain-text content of the clipboard ("" when empty)
HTML content	The rich-text representation, when present
formats present	Which content types the entry carries (text, HTML, image)
image presence/size	Whether an image was copied, and its byte size

Example Assertions

Click the "Copy link" button, then verify the clipboard contains "/invoice/42"
Verify the clipboard text is "INV-2026-042"
Verify an image was copied to the clipboard
Verify the clipboard text is empty

Example Extractions

Click the Copy button, store the copied coupon code as 'coupon'
Store the clipboard text as 'copied_link'

Stored values work like any other variable. Fill {{coupon}} into a field later, or assert on it.

Writing and Pasting (actions)

The clipboard isn’t read-only. Objectives can also drive it. See Browser State Actions:

Write "John Tester" to the clipboard, click the message field, then paste from the clipboard

Tips

Don’t paste to verify: assert on the clipboard directly instead of pasting into a field and reading it back
Prefer positive phrasing for empties: “verify the clipboard text is empty” rather than “verify X is not on the clipboard”
Clipboard actions need a page loaded first. Navigate before writing or pasting

​The Test Clipboard

​Planning for Multi-Step Tests

​What You Can Query

​Example Assertions

​Example Extractions

​Writing and Pasting (actions)

​Tips