Change record status: 
Project: 
Introduced in branch: 
8.4.x
Introduced in version: 
8.4.x
Description: 

\Drupal\FunctionalTests\AssertLegacyTrait::assertNoPattern($regex) is deprecated in favor of \Drupal\Tests\WebAssert::responseNotMatches($regex)

Within BrowserTestBase you can call it like this:

$this->assertSession()->responseNotMatches($regex);
Impacts: 
Module developers