Allow exact values in st.builds() arguments

[ketozhang]

Are there any strong opposition to allowing non-strategy objects in st.builds() positional and keyword arguments to be handled as exact values (i.e., as if it was passed in with st.just()?

Current Behavior

@given(st.builds(MyClass, x=st.integers(), y=st.just("foobar")))
def test():
  ...

Desired Behavior

@given(st.builds(MyClass, x==st.integers(), y="foobar"))
def test():
  ...

# Currently causes:
#       InvalidArgument: Expected a SearchStrategy but got mapping['y']='foobar' (type=str)

[Zac-HD]

Yes - it complicates the interface, which is a cost that grows surprisingly quickly and is disproportionately bad for complicated use-cases.

The current workarounds with just() or functools.partial() also seem fine to me, and I think that since these are necessary tools for complex use-cases there's some value in making them the idiomatic solution in simple cases too.

[ketozhang]

Well it's a UX consideration—I can never use hypothesis without constantly going referring back to What you can generate and how. Even so what keyword do I search for to figure out it's st.just().