diff --git a/src/accumulate/accumulate.jl b/src/accumulate/accumulate.jl
index e88fd18..0b00beb 100644
--- a/src/accumulate/accumulate.jl
+++ b/src/accumulate/accumulate.jl
@@ -139,7 +139,7 @@ end
 
 
 function accumulate!(
-    op, dst::AbstractArray, src::AbstractArray, backend::Backend=get_backend(v);
+    op, dst::AbstractArray, src::AbstractArray, backend::Backend=get_backend(dst);
     init,
     neutral=GPUArrays.neutral_element(op, eltype(dst)),
     dims::Union{Nothing, Int}=nothing,
diff --git a/test/runtests.jl b/test/runtests.jl
index d3ceca3..5907119 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -1307,9 +1307,9 @@ end
     for _ in 1:100
         num_elems = rand(1:100_000)
         x = array_from_host(rand(1:1000, num_elems), Int32)
-        y = copy(x)
+        y = similar(x)
         init = rand(-1000:1000)
-        AK.accumulate!(+, y; init=Int32(init))
+        AK.accumulate!(+, y, x; init=Int32(init))
         @test all(Array(y) .== accumulate(+, Array(x), init=init))
     end
 
@@ -1395,7 +1395,7 @@ end
             n3 = rand(1:100)
             vh = rand(Float32, n1, n2, n3)
             v = array_from_host(vh)
-            
+
             s = AK.accumulate(+, v; init=Float32(0), dims=dims)
             sh = Array(s)
             @test all(sh .≈ accumulate(+, vh, init=Float32(0), dims=dims))
@@ -1530,7 +1530,7 @@ end
     AK.searchsortedfirst(v, x, by=abs, lt=(>), rev=true, block_size=64)
     AK.searchsortedlast!(ix, v, x, by=abs, lt=(>), rev=true, block_size=64)
     AK.searchsortedlast(v, x, by=abs, lt=(>), rev=true, block_size=64)
- 
+
     vh = Array(v)
     xh = Array(x)
     ixh = similar(xh, Int32)
@@ -1809,7 +1809,7 @@ end
 
 
 @testset "cumsum" begin
-    
+
     Random.seed!(0)
 
     # Simple correctness tests
@@ -1858,7 +1858,7 @@ end
 
 
 @testset "cumprod" begin
-    
+
     Random.seed!(0)
 
     # Simple correctness tests