forAll sample size incorrectly set to constant 1

[cihleman3]

PropF.forAll { (s: String) => does not increase the size of the strings it is testing: it only uses strings of length 0 or 1.
(The same holds for lists and presumably for alle "size-sensitive" data, i.e., not numbers.)
The apparent reason is that the loop inside of check implementing the quantifier uses a constant size of 1:
val size = minSize.toDouble + sizeStep.

[arosien]

I think you mean that the sample size is incorrectly set to be constant (size 1!). Can you update the description? Saying "does not increase" implies the sample size increases, which is not technically correct; the sample size bounds are set (incorrectly!) and do not vary.

[arosien]

Re: constant size:

val sizeStep = (maxSize - minSize) / minSuccessfulTests
...
val size = minSize.toDouble + sizeStep

The default parameters are:

• maxSize = 100
• minSize = 0
• minSuccessfulTests = 100
  therefore size is set to 1.

[cihleman3]

Ok, is it clearer now?

[arosien]

Looking at the impl which computes this stepSize, it's not clear to me what it is for. Couldn't the size parameters be unmodified from their defaults, which would avoid the bug?

[mpilquist]

Wow, thanks for finding this one. I'm amazed we haven't noticed this behavior until now!