added tests, NEWS, and a bugfix

NEWS.md

@@ -52,6 +52,7 @@ New library functions
 * `tanpi` is now defined. It computes tan(πx) more accurately than `tan(pi*x)` ([#48575]).
 * `fourthroot(x)` is now defined in `Base.Math` and can be used to compute the fourth root of `x`.
    It can also be accessed using the unicode character `∜`, which can be typed by `\fourthroot<tab>` ([#48899]).
+* `unzip(itr)` is now provided, essentially as an inverse of `zip` ([#33515]).
 * `Libc.memmove`, `Libc.memset`, and `Libc.memcpy` are now defined, whose functionality matches that of their respective C calls.
 
 New library features

base/iterators.jl

@@ -13,7 +13,7 @@ using .Base:
     SizeUnknown, HasLength, HasShape, IsInfinite, EltypeUnknown, HasEltype, OneTo,
     @propagate_inbounds, @isdefined, @boundscheck, @inbounds, Generator,
     AbstractRange, AbstractUnitRange, UnitRange, LinearIndices, TupleOrBottom,
-    (:), |, +, -, *, !==, !, ==, !=, <=, <, >, >=, missing,
+    (:), |, +, -, *, !==, !, ==, !=, <=, <, >, >=, missing, something, copyto!,
     any, _counttuple, eachindex, ntuple, zero, prod, reduce, in, firstindex, lastindex,
     tail, fieldtypes, min, max, minimum, zero, oneunit, promote, promote_shape
 using Core: @doc

test/iterators.jl

@@ -1001,3 +1001,14 @@ end
     end
     @test v == ()
 end
+
+@testset "unzip" begin
+    for itrs in ((1:3,), (1:3, 4:6), (1:3,4:6,7:9),
+                 ((), ()), (Bool[], Int8[]),
+                 (Iterators.filter(isodd,1:6), 4:6))
+        @test unzip(zip(itrs...)) == collect.(itrs)
+    end
+    @test unzip([(), (), ()]) == ()
+    @test unzip([(1,2), (4,5,6)]) == ([1, 4], [2, 5])
+    @test unzip([(4,5,6), (1,2)]) == ([4, 1], [5, 2])
+end