test special cases of sum!

src/generic/AbstractBandedMatrix.jl

@@ -361,6 +361,8 @@ function sum!(ret::AbstractArray, A::AbstractBandedMatrix)
     else
         throw(DimensionMismatch("reduction on matrix of size ($n, $m) with output size $s"))
     end
+    #return the value to mimic Base.sum!
+    ret
 end
 
 function sum(A::AbstractBandedMatrix; dims=:)

test/test_sum.jl

@@ -2,6 +2,7 @@ module TestSum
 
 using Test, BandedMatrices, Random
 
+Random.seed!(0)
 r = brand(Float64,rand(1:10_000),rand(1:10_000),rand(-20:100),rand(-20:100))
 empty_r = brand(Float64,rand(1:1_000),rand(1:1_000),rand(1:100),rand(-200:-101))
 n,m = size(empty_r)
@@ -10,11 +11,20 @@ matr = Matrix(r)
     @test sum(empty_r) == 0
     @test sum(empty_r; dims = 2) == zeros(n,1)
     @test sum(empty_r; dims = 1) == zeros(1,m)
+
     @test sum(r) ≈ sum(matr) rtol = 1e-10
     @test sum(r; dims=2) ≈ sum(matr; dims=2) rtol = 1e-10
     @test sum(r; dims=1) ≈ sum(matr; dims=1) rtol = 1e-10
     @test sum(r; dims=3) == r
     @test_throws ArgumentError sum(r; dims=0)
+
+    v = [1.0]
+    sum!(v, r)
+    @test v == sum!(v, Matrix(r))
+    n2, m2 = size(r)
+    v = ones(Float64, n2)
+    @test sum!(v, r) == sum!(v, Matrix(r))
+    @test_throws DimensionMismatch sum!(zeros(Float64, n2 + 1, m2 + 1), r)
 end
 
 end