[Feature] Access to functional subroutine return values in tests

[richardmarshall]

Kind of proposals

• Testing

Describe the feature

When testing user defined functions that return values there is no direct way to access the return value in a test. Like testing.state it would be nice to have another testing variable containing the return value of the previous function call.

The idea is to be able to have a test written along the lines of:

sub test {
    testing.call_subroutine("returns_a_string");
    assert.equal(testing.return_value, "hi!");
}

Give us your considerations

testing.call_subroutine could be updated to store the return value of function subroutines along the lines of how it is storing state transitions in ctx.ReturnState. With that value stored in the context a new testing.return_value testing variable could be added to give tests access to this value.

[gandazgul]

I'm working on this one.