Add tests, simplify matmul

Author: mtfishman

src/abstractsparsearrayinterface.jl

@@ -359,9 +359,7 @@ function sparse_mul!(
   β::Number=false;
   (mul!!)=(default_mul!!),
 )
-  # TODO: Change to: `a_dest .*= β`
-  # once https://github.com/ITensor/SparseArraysBase.jl/issues/19 is fixed.
-  storedvalues(a_dest) .*= β
+  a_dest .*= β
   β′ = one(Bool)
   for I1 in eachstoredindex(a1)
     for I2 in eachstoredindex(a2)

test/basics/test_sparsearraydok.jl

@@ -177,4 +177,42 @@ arrayts = (Array,)
     a[1, 2] = 12
     @test sprint(show, "text/plain", a) == "$(summary(a)):\n ⋅  $(eltype(a)(12))\n ⋅    ⋅"
   end
+
+  # Regression test for:
+  # https://github.com/ITensor/SparseArraysBase.jl/issues/19
+  a = SparseArrayDOK{elt}(2, 2)
+  a[1, 1] = 1
+  a .*= 2
+  @test a == [2 0; 0 0]
+  @test storedlength(a) == 1
+
+  # Test aliasing behavior.
+  a = SparseArrayDOK{elt}(2, 2)
+  a[1, 1] = 11
+  a[1, 2] = 12
+  a[2, 2] = 22
+  c1 = @view a[:, 1]
+  r1 = @view a[1, :]
+  r1 .= c1
+  @test c1 == [11, 0]
+  @test storedlength(c1) == 1
+  @test r1 == [11, 0]
+  @test storedlength(r1) == 2
+  @test a == [11 0; 0 22]
+  @test storedlength(a) == 3
+
+  # Test aliasing behavior.
+  a = SparseArrayDOK{elt}(2, 2)
+  a[1, 1] = 11
+  a[1, 2] = 12
+  a[2, 2] = 22
+  c1 = @view a[:, 1]
+  r1 = @view a[1, :]
+  c1 .= r1
+  @test c1 == [11, 12]
+  @test storedlength(c1) == 2
+  @test r1 == [11, 12]
+  @test storedlength(r1) == 2
+  @test a == [11 12; 12 22]
+  @test storedlength(a) == 4
 end