Update test/rulesets/LinearAlgebra/structured.jl

Co-authored-by: Frames White <oxinabox@ucc.asn.au>

Author: ChrisRackauckas

test/rulesets/LinearAlgebra/structured.jl

@@ -163,7 +163,7 @@
     end
 
     @testset "Tridiagonal" begin
-        res, pb = rrule(Tridiagonal, [1, 4], [2, 3, 4], [5, 3])
+        test_rrule(Tridiagonal, [1.0, 4.0], [2.0, 3.0, 4.0], [5.0, 3.0])
         @test pb(10 * res) == (NoTangent(), [10, 40], [20, 30, 40], [50, 30])
     end
 end