Add tests

Author: jishnub

stdlib/LinearAlgebra/test/diagonal.jl

@@ -1235,4 +1235,12 @@ end
     end
 end
 
+@testset "avoid matmul ambiguities with ::MyMatrix * ::AbstractMatrix" begin
+    A = [i+j for i in 1:2, j in 1:2]
+    S = SizedArrays.SizedArray{(2,2)}(A)
+    D = Diagonal([1:2;])
+    @test S * D == A * D
+    @test D * S == D * A
+end
+
 end # module TestDiagonal

stdlib/LinearAlgebra/test/triangular.jl

@@ -8,6 +8,10 @@ using LinearAlgebra: BlasFloat, errorbounds, full!, transpose!,
     UnitUpperTriangular, UnitLowerTriangular,
     mul!, rdiv!, rmul!, lmul!
 
+const BASE_TEST_PATH = joinpath(Sys.BINDIR, "..", "share", "julia", "test")
+isdefined(Main, :SizedArrays) || @eval Main include(joinpath($(BASE_TEST_PATH), "testhelpers", "SizedArrays.jl"))
+using .Main.SizedArrays
+
 debug && println("Triangular matrices")
 
 n = 9
@@ -866,4 +870,12 @@ end
     end
 end
 
+@testset "avoid matmul ambiguities with ::MyMatrix * ::AbstractMatrix" begin
+    A = [i+j for i in 1:2, j in 1:2]
+    S = SizedArrays.SizedArray{(2,2)}(A)
+    U = UpperTriangular(ones(2,2))
+    @test S * U == A * U
+    @test U * S == U * A
+end
+
 end # module TestTriangular

test/testhelpers/SizedArrays.jl

@@ -46,4 +46,9 @@ function *(S1::SizedArrayLike, S2::SizedArrayLike)
     SZ = ndims(data) == 1 ? (size(S1, 1), ) : (size(S1, 1), size(S2, 2))
     SizedArray{SZ}(data)
 end
+
+# deliberately wide method defintion to ensure that this doesn't lead to ambiguities with
+# structured matrices
+*(S1::SizedArrayLike, M::AbstractMatrix) = _data(S1) * M
+
 end