Fix Fun show on union of Points (#470)

Author: jishnub

src/show.jl

@@ -12,7 +12,7 @@ end
 
 evalconst(f, ::AnyDomain) = f(0.0)
 evalconst(f, d) = f(leftendpoint(d))
-evalconst(f, d::Point) = f(d)
+evalconst(f, d::Union{Point, UnionDomain{<:Any, <:Tuple{Point, Vararg{Point}}}}) = f(d)
 
 function show(io::IO,f::Fun{<:Union{ConstantSpace, ArraySpace{<:ConstantSpace}}})
     d = domain(f)

test/show.jl

@@ -54,7 +54,11 @@
 		@test contains(repr(f), repr(f(0)))
 
 		f = Fun(1, ConstantSpace(Point(3)))
-		@test contains(repr(f), repr(Point(3)))
+		@test contains(repr(f), repr(domain(f)))
+		@test contains(repr(f), repr(1))
+
+		f = Fun(1, ConstantSpace(Point(3) ∪ Point(4)))
+		@test contains(repr(f), repr(domain(f)))
 		@test contains(repr(f), repr(1))
 	end
 	@testset "Operator" begin