user larger keys for IntMap tests

[jwaldmann]

Prompted by #787 (comment), I replaced the Arbitrary instance with

instance Arbitrary a => Arbitrary (IntMap a) where
  arbitrary = fmap (fromList . fmap (\(k,v) -> (getLarge k, v))) arbitrary

Good thing: all tests are green. So, no action required. We still might want to replace the instance?

That section of the code has heading Arbitrary, reasonably balanced trees. I think "reasonable" is the wrong goal here - for correctness tests, I want all sorts of data, including "unreasonable". This might be different from performance tests where we might want typical, and that could mean "small keys", as produced by the current instance.

[treeowl]

I certainly agree that we want extreme trees! Is Large a good way to get that? Or do we need to combine multiple generators? If you think this version is more thorough than what we did before, I'll happily merge.

Quick question: do you have any idea how to up the test count in CI?

[jwaldmann]

Is Large a good way to get that?

I have no idea, and no experience. Large looked to me like one standard way to quickly get Ints that use all bits. I found out about it only after I made the ad-hoc definition 2^x * y. Quickcheck's generator https://hackage.haskell.org/package/QuickCheck-2.14.2/docs/src/Test.QuickCheck.Arbitrary.html#arbitrarySizedBoundedIntegral is different (better?) in the sense that it will use all bits (mine would just shift a few-bit pattern). On the other hand, an Int with a long tail of zeroes might be useful for the specific data structures that we want to test.

If you think this version is more thorough than what we did before, I'll happily merge.

"more thorough" is hard to define/measure. One could fuzz the code and see how fast that's detected? (Nice student project ...)

Quick question: do you have any idea how to up the test count in CI?

On the command line, I used stack test --ta '-a 10000'. containers CI uses cabal, I'm sure it has a way to pass options. This seems to work:

cabal test intset-properties --test-option="-a 10000"

The CI script is generated? Then we need to find a way to pass options through the generator?

[treeowl]

I'll merge now. We can investigate more options later.

[treeowl]

Oh wait, this isn't a PR. 🤦

[jwaldmann]

I can make a PR. For both IntMap and IntSet?

[treeowl]

Thanks.

…

On Thu, Jul 22, 2021, 11:36 AM jwaldmann ***@***.***> wrote: I can make a PR. — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#788 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAOOF7LIRM65INTSETUDHFTTZA3JVANCNFSM5AZ4JYFA> .

[treeowl]

Why didn't I merge this already?

[jwaldmann]

ping

[meooow25]

Arbitrary IntMap tests with large keys now.

containers/containers-tests/tests/intmap-properties.hs

Lines 229 to 232 in 5d4bc2e

	instance Arbitrary a => Arbitrary (IntMap a) where
	arbitrary = oneof [go arbitrary, go (getLarge <$> arbitrary)]
	where
	go kgen = fromList <$> listOf ((,) <$> kgen <*> arbitrary)