fix prodfactor(factor(1)) (was an error) (#51)

Author: rfourquet

src/Primes.jl

@@ -362,7 +362,7 @@ julia> prodfactors(factor(100))
 """
 function prodfactors end
 
-prodfactors(factors::Associative) = prod(p^i for (p, i) in factors)
+prodfactors{K}(factors::Associative{K}) = isempty(factors) ? one(K) : prod(p^i for (p, i) in factors)
 prodfactors(factors::Union{AbstractArray, Set, IntSet}) = prod(factors)
 
 """

test/runtests.jl

@@ -372,7 +372,8 @@ end
 end
 
 for T in (Int, UInt, BigInt)
-    for n in rand(T(1):T(100000), 10)
+    for n in [T(1); rand(T(2):T(100000), 10)]
+        # for n=T(1), must not error out (#51)
         for C = (Factorization, Vector, Dict)
             @test prodfactors(factor(C, n)) == n
         end