do not drop repeat keys in Accumulate(::Pairs...) (#861)

src/accumulator.jl

@@ -14,7 +14,13 @@ end
 
 Accumulator{T, V}() where {T, V} = Accumulator{T, V}(Dict{T, V}())
 Accumulator(map::AbstractDict) = Accumulator(Dict(map))
-Accumulator(ps::Pair...) = Accumulator(Dict(ps))
+function Accumulator(p::Pair, ps::Pair...)
+    a = Accumulator(Dict(p))
+    for (k,v) in ps
+        inc!(a, k, v)
+    end
+    a
+end
 
 counter(T::Type) = Accumulator{T, Int}()
 counter(dct::AbstractDict{T, V}) where {T, V<:Integer} = Accumulator{T, V}(Dict(dct))

test/test_accumulator.jl

@@ -51,7 +51,7 @@
         @test sum(ct) == 6
     end
 
-    @testset "From Pairs" begin 
+    @testset "From Pairs" begin
         acc = Accumulator("a" => 2, "b" => 3, "c" => 1)
         @test isa(acc,Accumulator{String,Int})
         @test haskey(acc,"a")
@@ -62,6 +62,15 @@
         @test acc["c"] == 1
     end
 
+    @testset "From Pairs with repeats" begin
+        acc = Accumulator("a" => 2, "b" => 3, "b" => 1)
+        @test isa(acc,Accumulator{String,Int})
+        @test haskey(acc,"a")
+        @test haskey(acc,"b")
+        @test acc["a"] == 2
+        @test acc["b"] == 4
+    end
+
     @testset "From Vector" begin
         ct2 = counter(["a", "a", "b", "b", "a", "c", "c"])
         @test isa(ct2, Accumulator{String,Int})