Add iteration helper

[earthboundkid]

It's a pain to test iterators because you need to break early to get complete code coverage. Add a helper for this.

[earthboundkid]

be.PartialSeq(t, it, 1, 2, 3) and be.WholeSeq(t, it, 1, 2, 3) maybe where WholeSeq will complain if the sequence keeps going and Partial will just break early.

[earthboundkid]

Okay, what if there's just

package testseq

func CollectN[T any](t testing.TB, seq iter.Seq[T], limit int, exhaustive bool) []T
func CollectN2[K, V any](t testing.TB, seq iter.Seq2[K, V], limit int, exhaustive bool) ([]K, []V)

And then you use AllEqual or whatever on the slice?

[earthboundkid]

Maybe

package testseq

func Equal[T comparable](t, seq, ...T) // Exhaustive
func CollectN[T any](t testing.TB, seq iter.Seq[T], limit int) []T // Exhaustive
func CollectN2[K, V any](t testing.TB, seq iter.Seq2[K, V], limit int) ([]K, []V)
func FirstN[T any](t testing.TB, seq iter.Seq[T], limit int) []T // Not exhaustive
func FirstN2[K, V any](t testing.TB, seq iter.Seq2[K, V], limit int) ([]K, []V)

[earthboundkid]

New idea:

package testseq

func Equal[T comparable](t, seq, ...T) // Exhaustive
func TakeN[T any](t testing.TB, seq iter.Seq[T], limit int) iter.Seq[T] // Exhaustive
func TakeN2[K, V any](t testing.TB, seq iter.Seq2[K, V], limit int) iter.Seq2[K, V]
func FirstN[T any](t testing.TB, seq iter.Seq[T], limit int) iter.Seq[T] // Not exhaustive
func FirstN2[K, V any](t testing.TB, seq iter.Seq2[K, V], limit int) iter.Seq2[K, V]

[earthboundkid]

package testseq

func Equal[T comparable](t, seq, ...T) // Exhaustive
type TakeLimit int8
const (
    Equals TakeLimit = iota
    AtMost
    AtLeast
)
func TakeN[T any](t testing.TB, seq iter.Seq[T], kind TakeLimit, limit int) iter.Seq[T]
func TakeN2[K, V any](t testing.TB, seq iter.Seq2[K, V], kind TakeLimit, limit int) iter.Seq2[K, V]

[earthboundkid]

IDK, I tried using this for https://github.com/earthboundkid/walker and I didn't need it. Maybe it's enough to just use slices.Collect.