Test output values and shapes

test/ext/test_DataInterpolations.jl

@@ -1,4 +1,6 @@
 using SparseConnectivityTracer
+using SparseConnectivityTracer: DEFAULT_GRADIENT_TRACER, DEFAULT_HESSIAN_TRACER
+using SparseConnectivityTracer: trace_input, Dual, primal
 using DataInterpolations
 using DataInterpolations: AbstractInterpolation
 using Test
@@ -77,6 +79,33 @@ function test_interpolation(t::InterpolationTest{N}) where {N} # N ≠ 1
     end
 end
 
+myprimal(x) = x
+myprimal(d::Dual) = primal(d)
+
+function test_output(t::InterpolationTest)
+    @testset "Output sizes and values" begin
+        out_ref = t.interp(tquery)
+        s_ref = size(out_ref)
+
+        @testset "$T" for T in (DEFAULT_GRADIENT_TRACER, DEFAULT_HESSIAN_TRACER)
+            t_tracer = trace_input(T, tquery)
+            out_tracer = t.interp(t_tracer)
+            s_tracer = size(out_tracer)
+            @test s_tracer == s_ref
+        end
+        @testset "$T" for T in (
+            Dual{typeof(tquery),DEFAULT_GRADIENT_TRACER},
+            Dual{typeof(tquery),DEFAULT_HESSIAN_TRACER},
+        )
+            t_dual = trace_input(T, tquery)
+            out_dual = t.interp(t_dual)
+            s_dual = size(out_dual)
+            @test s_dual == s_ref
+            @test myprimal.(out_dual) ≈ out_ref
+        end
+    end
+end
+
 #===========#
 # Run tests #
 #===========#
@@ -93,9 +122,9 @@ interpolation_tests = (
     InterpolationTest(1, CubicSpline(uv, t)),
 )
 
-
 @testset "Test interpolations" begin
     @testset "$(name(t))" for t in interpolation_tests
         test_interpolation(t)
+        test_output(t)
     end
 end