--- a/test/SbpOperators/volumeops/derivatives/second_derivative_test.jl	Mon Feb 21 10:33:58 2022 +0100
+++ b/test/SbpOperators/volumeops/derivatives/second_derivative_test.jl	Fri Feb 03 22:14:47 2023 +0100
@@ -6,8 +6,11 @@
 
 import Sbplib.SbpOperators.VolumeOperator
 
+# TODO: Refactor these test to look more like the tests in first_derivative_test.jl.
+
 @testset "SecondDerivative" begin
-    stencil_set = read_stencil_set(sbp_operators_path()*"standard_diagonal.toml"; order=4)
+    operator_path = sbp_operators_path()*"standard_diagonal.toml"
+    stencil_set = read_stencil_set(operator_path; order=4)
     inner_stencil = parse_stencil(stencil_set["D2"]["inner_stencil"])
     closure_stencils = parse_stencil.(stencil_set["D2"]["closure_stencils"])
     Lx = 3.5
@@ -17,16 +20,19 @@
 
     @testset "Constructors" begin
         @testset "1D" begin
-            Dₓₓ = second_derivative(g_1D,inner_stencil,closure_stencils)
-            @test Dₓₓ == second_derivative(g_1D,inner_stencil,closure_stencils,1)
+            Dₓₓ = second_derivative(g_1D,inner_stencil,closure_stencils,1)
+            @test Dₓₓ == second_derivative(g_1D,inner_stencil,closure_stencils)
+            @test Dₓₓ == second_derivative(g_1D,stencil_set,1)
+            @test Dₓₓ == second_derivative(g_1D,stencil_set)
             @test Dₓₓ isa VolumeOperator
         end
         @testset "2D" begin
             Dₓₓ = second_derivative(g_2D,inner_stencil,closure_stencils,1)
-            D2 = second_derivative(g_1D,inner_stencil,closure_stencils)
-            I = IdentityMapping{Float64}(size(g_2D)[2])
+            D2 = second_derivative(g_1D,inner_stencil,closure_stencils,1)
+            I = IdentityTensor{Float64}(size(g_2D)[2])
             @test Dₓₓ == D2⊗I
-            @test Dₓₓ isa TensorMapping{T,2,2} where T
+            @test Dₓₓ == second_derivative(g_2D,stencil_set,1)
+            @test Dₓₓ isa LazyTensor{T,2,2} where T
         end
     end
 
@@ -47,10 +53,8 @@
             # 2nd order interior stencil, 1nd order boundary stencil,
             # implies that L*v should be exact for monomials up to order 2.
             @testset "2nd order" begin
-                stencil_set = read_stencil_set(sbp_operators_path()*"standard_diagonal.toml"; order=2)
-                inner_stencil = parse_stencil(stencil_set["D2"]["inner_stencil"])
-			    closure_stencils = parse_stencil.(stencil_set["D2"]["closure_stencils"])
-                Dₓₓ = second_derivative(g_1D,inner_stencil,closure_stencils)
+                stencil_set = read_stencil_set(operator_path; order=2)
+                Dₓₓ = second_derivative(g_1D,stencil_set)
                 @test Dₓₓ*monomials[1] ≈ zeros(Float64,size(g_1D)...) atol = 5e-10
                 @test Dₓₓ*monomials[2] ≈ zeros(Float64,size(g_1D)...) atol = 5e-10
                 @test Dₓₓ*monomials[3] ≈ monomials[1] atol = 5e-10
@@ -60,10 +64,8 @@
             # 4th order interior stencil, 2nd order boundary stencil,
             # implies that L*v should be exact for monomials up to order 3.
             @testset "4th order" begin
-                stencil_set = read_stencil_set(sbp_operators_path()*"standard_diagonal.toml"; order=4)
-                inner_stencil = parse_stencil(stencil_set["D2"]["inner_stencil"])
-			    closure_stencils = parse_stencil.(stencil_set["D2"]["closure_stencils"])
-                Dₓₓ = second_derivative(g_1D,inner_stencil,closure_stencils)
+                stencil_set = read_stencil_set(operator_path; order=4)
+                Dₓₓ = second_derivative(g_1D,stencil_set)
                 # NOTE: high tolerances for checking the "exact" differentiation
                 # due to accumulation of round-off errors/cancellation errors?
                 @test Dₓₓ*monomials[1] ≈ zeros(Float64,size(g_1D)...) atol = 5e-10
@@ -88,10 +90,8 @@
             # 2nd order interior stencil, 1st order boundary stencil,
             # implies that L*v should be exact for binomials up to order 2.
             @testset "2nd order" begin
-                stencil_set = read_stencil_set(sbp_operators_path()*"standard_diagonal.toml"; order=2)
-                inner_stencil = parse_stencil(stencil_set["D2"]["inner_stencil"])
-                closure_stencils = parse_stencil.(stencil_set["D2"]["closure_stencils"])
-                Dyy = second_derivative(g_2D,inner_stencil,closure_stencils,2)
+                stencil_set = read_stencil_set(operator_path; order=2)
+                Dyy = second_derivative(g_2D,stencil_set,2)
                 @test Dyy*binomials[1] ≈ zeros(Float64,size(g_2D)...) atol = 5e-9
                 @test Dyy*binomials[2] ≈ zeros(Float64,size(g_2D)...) atol = 5e-9
                 @test Dyy*binomials[3] ≈ evalOn(g_2D,(x,y)->1.) atol = 5e-9
@@ -101,10 +101,8 @@
             # 4th order interior stencil, 2nd order boundary stencil,
             # implies that L*v should be exact for binomials up to order 3.
             @testset "4th order" begin
-                stencil_set = read_stencil_set(sbp_operators_path()*"standard_diagonal.toml"; order=4)
-                inner_stencil = parse_stencil(stencil_set["D2"]["inner_stencil"])
-                closure_stencils = parse_stencil.(stencil_set["D2"]["closure_stencils"])
-                Dyy = second_derivative(g_2D,inner_stencil,closure_stencils,2)
+                stencil_set = read_stencil_set(operator_path; order=4)
+                Dyy = second_derivative(g_2D,stencil_set,2)
                 # NOTE: high tolerances for checking the "exact" differentiation
                 # due to accumulation of round-off errors/cancellation errors?
                 @test Dyy*binomials[1] ≈ zeros(Float64,size(g_2D)...) atol = 5e-9