Assert how many records the grid found ("19 records found" in its toolbar), over all its pages.
Examples
Then the grid should show 19 records
Then the grid should show 1 record
And the grid should show 0 records
Then the grid should show 2040 records
Then the grid should show 4 records
Pattern
Then(/^the grid should show (\d+) records?$/, …)
Part of @webship-js/magento-steps (github.com/webship/magento-steps), a step pack for Webship-js 2.0.x.