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How to combine quickcheck 1+ with fake? #320
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I've encountered the same issue. I solved it in a hacky way by reimplementing SafeEmail. #[cfg(test)]
mod tests {
use fake::locales::{self, Data};
use quickcheck::{Arbitrary, Gen};
#[derive(Debug, Clone)]
struct ValidEmailFixture(pub String);
impl Arbitrary for ValidEmailFixture {
fn arbitrary(g: &mut Gen) -> Self {
let username = g
.choose(locales::EN::NAME_FIRST_NAME)
.unwrap()
.to_lowercase();
let domain = g.choose(&["com", "net", "org"]).unwrap();
let email = format!("{username}@example.{domain}");
Self(email)
}
}
#[quickcheck_macros::quickcheck]
fn valid_emails_are_parsed_successfully(email: ValidEmailFixture) -> bool {
SubscriberEmail::parse(email.0).is_ok()
}
} Not ideal but also not too bad. Zero to Production's author, Luca Palmieri, posted an excerpt that covers OP's code above if anyone wants to follow along. |
Same issue here @BurntSushi. How to use |
An extension for more context if you came here from the same book - This is exactly how fake is implmenting the safeEmail function. impl<L: Data + Copy> Dummy<SafeEmail<L>> for String {
fn dummy_with_rng<R: Rng + ?Sized>(c: &SafeEmail<L>, rng: &mut R) -> Self {
let username: String = FirstName(c.0).fake_with_rng::<&str, _>(rng).to_lowercase();
let domain = ["com", "net", "org"].choose(rng).unwrap();
format!("{}@example.{}", username, domain)
}
} For more information, there is #265 to read for why rng is no longer a dependency. Enough Digging, Enjoy coding :3 |
...and switch the 32-bit integer parser to just exhaustive checking. (More on that later.) Why move away from QuickCheck? 1. The maintainer appears to have little interest in actually maintaining it. BurntSushi/quickcheck#315 2. Its API is incredibly inefficient, especially on failure, and it's far too rigid for my needs. For one, I need something looser than `Arbitrary: Clone` so things like `std::io::Error` can be generated more easily. Also, with larger structures, efficiency will directly correlate to faster test runs. Also, I've run into the limitations of not being able to access the underlying random number generator far too many times to count, as I frequently need to generate random values within ranges, among other things. - BurntSushi/quickcheck#279 - BurntSushi/quickcheck#312 - BurntSushi/quickcheck#320 - BurntSushi/quickcheck#267 3. It correctly limits generated `Vec` and `String` length, but it doesn't similarly enforce limits on test length. 4. There's numerous open issues in it that I've addressed, in some cases by better core design. To name a few particularly bad ones: - Misuse of runtime bounds in `Duration` generation, `SystemTime` generation able to panic for unrelated reasons: BurntSushi/quickcheck#321 - Incorrect generation of `SystemTime`: BurntSushi/quickcheck#321 - Unbounded float shrinkers: BurntSushi/quickcheck#295 - Avoiding pointless debug string building: BurntSushi/quickcheck#303 - Signed shrinker shrinks to the most negative value, leading to occasional internal panics: BurntSushi/quickcheck#301 There's still some room for improvement, like switching away from a recursive loop: BurntSushi/quickcheck#285. But, this is good enough for my use cases right now. And this code base is structured such that such a change is *much* easier to do. (It's also considerably simpler.) As for the integer parser change, I found a way to re-structure it so I could perform true exhaustive testing on it. Every code path has every combination of inputs tested, except for memory space as a whole. This gives me enough confidence that I can ditch the randomized property checking for it.
Following the zero2production book With
quickcheck = "0.9.2"
,quickcheck_macros = "0.9.1"
andfake = "~2.3"
, the following works, because the functionArbitrary::arbitrary
expected aGen
trait, andGen
used to be a trait:Then we pass the mutable reference
g
intoSafeEmail().fake_with_rng(g);
and it works -fake
generates random valid emails.However, in
quickcheck = "1"
,quickcheck::Gen
is no trait anymore, only a struct. I haven't found out how to access the innerrng: rand::rngs::SmallRng
ofGen
to pass it intoSafeEmail().fake_with_rng
and getfake
to work withquickcheck
.How is it still possible in 1+?
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