document that srand() returns the passed RNG

JuliaLang · Apr 1, 2017 · ad66758 · ad66758
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diff --git a/base/random.jl b/base/random.jl
@@ -220,7 +220,7 @@ end
 ## srand()
 
 """
- srand([rng=GLOBAL_RNG], [seed])
+ srand([rng=GLOBAL_RNG], [seed]) -> rng
 
 Reseed the random number generator. If a `seed` is provided, the RNG will give a
 reproducible sequence of numbers, otherwise Julia will get entropy from the system. For

diff --git a/test/random.jl b/test/random.jl
@@ -479,3 +479,18 @@ let seed = rand(UInt32, 10)
  resize!(seed, 4)
  @test r.seed != seed
 end
+
+# srand(rng, ...) returns rng (#21248)
+let g = Base.Random.GLOBAL_RNG,
+ m = MersenneTwister(0)
+ @test srand() === g
+ @test srand(rand(UInt)) === g
+ @test srand(rand(UInt32, rand(1:10))) === g
+ @test srand(@__FILE__) === g
+ @test srand(@__FILE__, rand(1:10)) === g
+ @test srand(m) === m
+ @test srand(m, rand(UInt)) === m
+ @test srand(m, rand(UInt32, rand(1:10))) === m
+ @test srand(m, rand(1:10)) === m
+ @test srand(m, @__FILE__, rand(1:10)) === m
+end