Then the membership form should show "Sign in"

A text in (or, with "not", absent from) the membership form: its heading, a validation message, or what it reports after it was submitted.

Examples

Then the membership form should show "Sign in"
Then the membership form should show "Enter your email address"
Then the membership form should show "Now check your email!"
Then the membership form should not show "Now check your email!"
And the membership form should show "Your account"

Pattern

Then(/^the membership form should( not)? show "([^"]*)"$/, …)

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