Use TestUtils for DCT adjoint tests

Author: gaurav-arya

test/runtests.jl

@@ -578,28 +578,19 @@ end
     end
 end
 
-@testset "adjoint" begin
+@testset "DCT adjoints" begin
     for x in (randn(3), randn(4), randn(3, 4), randn(3, 4, 5))
         y = randn(size(x))
         N = ndims(x)
         for dims in unique((1, 1:N, N))
-
-            # DCT/ IDCT
             for P in (plan_dct(x, dims), plan_idct(x, dims))
-                @test (P')' * x == P * x
-                @test size(P') == AbstractFFTs.output_size(P)
-                @test dot(y, P * x) ≈ dot(P' * y, x)
-                @test dot(y, P \ x) ≈ dot(P' \ y, x)
-            end # P
-        end # dims
-    end # x
+                AbstractFFTs.TestUtils.test_plan_adjoint(P, x)
+            end
+        end
+    end
 end
 
 @testset "AbstractFFTs FFT backend tests" begin
     AbstractFFTs.TestUtils.test_complex_ffts(Array)
     AbstractFFTs.TestUtils.test_real_ffts(Array; copy_input=true)
 end
-
-@testset "ChainRules" begin
-
-end