added rand for TypedEndpointsInterval (#116)

* added rand for TypedEndpointsInterval

* disallow rand(::TypedInterval{:closed, :open})

Author: zsunberg

src/interval.jl

@@ -222,11 +222,11 @@ end
 
 # random sampling from interval
 Random.gentype(::Type{Interval{L,R,T}}) where {L,R,T} = float(T)
-function Random.rand(rng::AbstractRNG, i::Random.SamplerTrivial{ClosedInterval{T}}) where {T<:Real}
+function Random.rand(rng::AbstractRNG, i::Random.SamplerTrivial{<:TypedEndpointsInterval{:closed, :closed, T}}) where T<:Real
     _i = i[]
     isempty(_i) && throw(ArgumentError("The interval should be non-empty."))
     a,b = endpoints(_i)
-    t = rand(rng, float(T))
+    t = rand(rng, float(T)) # technically this samples from [0, 1), but we still allow it with TypedEndpointsInterval{:closed, :closed} for convenience
     return clamp(t*a+(1-t)*b, _i)
 end
 

test/runtests.jl

@@ -769,6 +769,11 @@ struct IncompleteInterval <: AbstractInterval{Int} end
             rand(i4,10) ⊆ i4
             rand(i5,10) ⊆ i5
         end
+
+        # special test to catch issue mentioned at the end of https://github.com/JuliaApproximation/DomainSets.jl/pull/112
+        struct RandTestUnitInterval <: TypedEndpointsInterval{:closed, :closed, Float64} end
+        IntervalSets.endpoints(::RandTestUnitInterval) = (-1.0, 1.0)
+        @test rand(RandTestUnitInterval()) in -1.0..1.0
     end
 
     @testset "IteratorSize" begin