What language runtime provides mocking/spy support? This seems excessively catered to IOC OO design, not the kind of thing a multi-paradigm language usually supports.
AFAIK deno ships with "test" as a sub command - having access to mock/spy seems reasonable in that context. It sort of follows from the "batteries included".
Just like deno bundles typescript - there is a reasonable expectation to track latest stable typescript features.
