Then the editor should contain "This is the welcome post."

A text in (or, with "not", absent from) the body of the post or page in the editor.

Examples

Then the editor should contain "This is the welcome post."
Then the editor should contain "The first paragraph."
Then the editor should not contain "Lorem ipsum"
And the editor should contain "A second heading"
Then the editor should not contain "deleted words"

Pattern

Then(/^the editor should( not)? contain "([^"]*)"$/, …)

Part of @webship-js/ghost-steps (github.com/webship/ghost-steps), a step pack for Webship-js 2.0.x.