Add rand(X) for Intervals and IntervalBoxes (#260)

* Add rand(X) for Intervals and IntervalBoxes

* Add StaticArrays to test file

* Correct tests

Author: dpsanders

src/IntervalArithmetic.jl

@@ -33,7 +33,7 @@ import Base:
     expm1, log1p,
     precision,
     isfinite, isnan, isinf, iszero,
-    abs, abs2, 
+    abs, abs2,
     show,
     isinteger, setdiff,
     parse, hash
@@ -112,6 +112,7 @@ include("multidim/multidim.jl")
 include("bisect.jl")
 include("decorations/decorations.jl")
 
+include("rand.jl")
 include("parsing.jl")
 include("display.jl")
 

src/rand.jl

@@ -0,0 +1,3 @@
+Base.rand(X::Interval{T}) where {T} = X.lo + rand(T) * (X.hi - X.lo)
+
+Base.rand(X::IntervalBox) = rand.(X)

test/rand.jl

@@ -0,0 +1,25 @@
+using IntervalArithmetic
+using Test
+using StaticArrays
+
+@testset "rand tests" begin
+
+    X = 3..4
+    for i in 1:100
+        @test rand(X) ∈ X
+    end
+
+    Y = IntervalBox(3..4, 5..6)
+    for i in 1:100
+        @test rand(Y) ∈ Y
+    end
+
+    for T in (Float32, Float64, BigFloat)
+        X = Interval{T}(3, 4)
+        @test rand(X) isa T
+
+        Y = IntervalBox(X, X)
+        @test rand(Y) isa SVector{2,T}
+    end
+
+end

test/runtests.jl

@@ -15,6 +15,8 @@ setformat(:full)
 include("interval_tests/intervals.jl")
 include("decoration_tests/decoration_tests.jl")
 
+include("rand.jl")
+
 # Display tests:
 include("display_tests/display.jl")