Overrides the real Date object and timer functions with fake ones that can be controlled through the fake time instance.

Make an assertion, error will be thrown if expr does not have truthy value.

Make an assertion that actual includes expected. If not then throw.

Executes a function, expecting it to throw. If it does not, then it throws.

Ensures that the file exists. If the file that is requested to be created is in directories that do not exist. these directories are created. If the file already exists, it is NOTMODIFIED. Requires the --allow-read and --allow-write flag.