Add tests

Author: dlfivefifty

src/bases/bases.jl

@@ -690,6 +690,7 @@ diff_layout(::ExpansionLayout, A, dims...) = diff_layout(ApplyLayout{typeof(*)}(
 ####
 
 simplifiable(::Mul{<:AdjointBasisLayout, <:AbstractBasisLayout}) = Val(true)
+@inline simplifiable(L::Mul{<:AdjointBasisLayout,ApplyLayout{typeof(*)}}) = simplifiable(*, L.A, first(arguments(*, L.B)))
 function copy(M::Mul{<:AdjointBasisLayout, <:AbstractBasisLayout})
     A = (M.A)'
     A == M.B && return grammatrix(A)

test/test_chebyshev.jl

@@ -167,6 +167,10 @@ Base.:(==)(::FooBasis, ::FooBasis) = true
         @test T'ã isa Vector
         @test T'*(ã .* ã) isa Vector
         @test (2T)'*(a .* T) isa Matrix
+        @test T'*(2T) isa Matrix
+        @test T'*(2T*randn(5)) isa Vector
+        @test LazyArrays.simplifiable(*, T', T*(1:5)) == Val(true)
+        @test (2T)'*(T*(1:5)) ≈ T'*(2T*(1:5)) ≈ T'BroadcastQuasiMatrix(*, 2, T*(1:5))
     end
 
     @testset "sum/dot/diff" begin

test/test_splines.jl

@@ -362,7 +362,7 @@ import ContinuumArrays: basis, AdjointBasisLayout, ExpansionLayout, BasisLayout,
         @test Δ == -(*(B',D',D,B))
         @test Δ == -(B'D'D*B)
         @test Δ == -((B'D')*(D*B))
-        @test_broken Δ == -B'*(D'D)*B
+        @test Δ == -B'*(D'D)*B
         @test Δ == -(B'*(D'D)*B)
 
         f = L*exp.(L.points) # project exp(x)