diff --git a/ext/MeshIntegralsEnzymeExt.jl b/ext/MeshIntegralsEnzymeExt.jl
index f78ad6b3..ab4bf82c 100644
--- a/ext/MeshIntegralsEnzymeExt.jl
+++ b/ext/MeshIntegralsEnzymeExt.jl
@@ -21,8 +21,8 @@ MeshIntegrals.supports_autoenzyme(::Type{<:Meshes.Geometry}) = true
 MeshIntegrals.supports_autoenzyme(::Type{<:Meshes.Domain}) = true
 # except for those that throw errors (see GitHub Issue #154)
 MeshIntegrals.supports_autoenzyme(::Type{<:Meshes.BezierCurve}) = false
-MeshIntegrals.supports_autoenzyme(::Type{<:Meshes.CylinderSurface}) = false
 MeshIntegrals.supports_autoenzyme(::Type{<:Meshes.Cylinder}) = false
+MeshIntegrals.supports_autoenzyme(::Type{<:Meshes.CylinderSurface}) = false
 MeshIntegrals.supports_autoenzyme(::Type{<:Meshes.ParametrizedCurve}) = false
 
 end
diff --git a/test/utils.jl b/test/utils.jl
index 847927f3..01181cb7 100644
--- a/test/utils.jl
+++ b/test/utils.jl
@@ -9,12 +9,14 @@ end
 
 @testitem "Utilities" setup=[Utils] begin
     # _KVector
-    v = Meshes.Vec(3, 4)
-    @test norm(MeshIntegrals._KVector(v)) ≈ 5.0u"m"
+    let v = Meshes.Vec(3, 4)
+        @test norm(MeshIntegrals._KVector(v)) ≈ 5.0u"m"
+    end
 
     # _units
-    p = Point(1.0u"cm", 2.0u"mm", 3.0u"m")
-    @test _units(p) == u"m"
+    let p = Point(1.0u"cm", 2.0u"mm", 3.0u"m")
+        @test _units(p) == u"m"
+    end
 
     # _zeros
     @test _zeros(2) == (0.0, 0.0)
@@ -25,37 +27,50 @@ end
     @test _ones(Float32, 2) == (1.0f0, 1.0f0)
 end
 
-@testitem "Differentiation (EnzymeExt loaded)" setup=[Utils] begin
-    # supports_autoenzyme(::Type{<:Any})
-    @test MeshIntegrals.supports_autoenzyme(Nothing) == false
-
-    # _default_diff_method -- using type or instance, Enzyme-supported combination
+@testitem "Differentiation (MeshIntegralsEnzymeExt loaded)" setup=[Utils] begin
+    # supports_autoenzyme & _default_diff_method
+    # Nominal usage: Enzyme-supported geometry and FP type
     let sphere = Sphere(Point(0, 0, 0), 1.0)
         @test _default_diff_method(Meshes.Sphere, Float64) isa AutoEnzyme
         @test _default_diff_method(sphere, Float64) isa AutoEnzyme
     end
-
-    # _default_diff_method -- Enzyme-unsupported FP types
+    # supports_autoenzyme(::Type{<:Any}) for CI completeness
+    @test MeshIntegrals.supports_autoenzyme(Nothing) == false
+    # BezierCurve: blocked by upstream Meshes-Enzyme incompatibility
+    let curve = BezierCurve([Point(t, 0) for t in range(-π, π, length = 361)])
+        @test_throws "proven readonly" jacobian(curve, (0.5,), AutoEnzyme())
+        @test _default_diff_method(Meshes.BezierCurve, Float64) isa FiniteDifference
+    end
+    # Cylinder: blocked by version-dependent upstream Meshes-Enzyme incompatibility
+    let cyl = Cylinder(Point(0, 0, 0), Point(0, 0, 1), 2.0)
+        @test _default_diff_method(Meshes.Cylinder, Float64) isa FiniteDifference
+    end
+    # CylinderSurface: blocked by version-dependent upstream Meshes-Enzyme incompatibility
+    let cylsurf = CylinderSurface(Point(0, 0, 0), Point(0, 0, 1), 2.0)
+        @test _default_diff_method(Meshes.CylinderSurface, Float64) isa FiniteDifference
+    end
+    # ParametrizedCurve: parametric functions are user-defined, can't guarantee behavior
+    @test _default_diff_method(Meshes.ParametrizedCurve, Float64) isa FiniteDifference
+    # Non-Float64: other FP types not supported by Enzyme
     @test _default_diff_method(Meshes.Sphere, Float16) isa FiniteDifference
     @test _default_diff_method(Meshes.Sphere, BigFloat) isa FiniteDifference
 
-    # _default_diff_method -- geometries that currently error with AutoEnzyme
-    @test _default_diff_method(Meshes.BezierCurve, Float64) isa FiniteDifference
-    @test _default_diff_method(Meshes.CylinderSurface, Float64) isa FiniteDifference
-    @test _default_diff_method(Meshes.Cylinder, Float64) isa FiniteDifference
-    @test _default_diff_method(Meshes.ParametrizedCurve, Float64) isa FiniteDifference
-
     # FiniteDifference
-    @test FiniteDifference().ε ≈ 1e-6
+    let diff = FiniteDifference()
+        @test typeof(diff.ε) == Float64
+        @test diff.ε ≈ 1e-6
+    end
 
     # Two-argument jacobian
-    segment = Segment(Point(0), Point(1))
-    @test MeshIntegrals.jacobian(segment, (0.5,)) == (Vec(1),)
+    let segment = Segment(Point(0), Point(1))
+        @test MeshIntegrals.jacobian(segment, (0.5,)) == (Vec(1),)
+    end
 
     # Test jacobian with wrong number of parametric coordinates
-    box = Box(Point(0, 0), Point(1, 1))
-    @test_throws ArgumentError jacobian(box, zeros(3), FiniteDifference())
-    @test_throws ArgumentError jacobian(box, zeros(3), AutoEnzyme())
+    let box = Box(Point(0, 0), Point(1, 1))
+        @test_throws ArgumentError jacobian(box, zeros(3), FiniteDifference())
+        @test_throws ArgumentError jacobian(box, zeros(3), AutoEnzyme())
+    end
 end
 
 @testitem "_ParametricGeometry" setup=[Utils] begin