Expect that a condition holds.Source:
Object to test.
Supports limited unquoting to make it easier to generate readable failures within a function or for loop. See quasi_label for more details.
a function that returns whether or not the condition is met, and if not, an error message to display.
Extra information to be included in the message. This argument is soft-deprecated and should not be used in new code. Instead see alternatives in quasi_label.
Used to customise failure messages. For expert use only.
This style of testing is formally deprecated as of the 3rd edition.
Use a more specific
expect_ function instead.
fail() for an expectation that always fails.