add missing test file

test/interface/clip_scale.jl

@@ -0,0 +1,67 @@
+
+@testset "interface ClipScale" begin
+    @testset "MvLocationScale" begin
+        @testset "$(string(covtype)) $(realtype) $(bijector)" for covtype in
+                                                                  [:meanfield, :fullrank],
+            realtype in [Float32, Float64],
+            bijector in [nothing, :identity]
+
+            d = 5
+            μ = zeros(realtype, d)
+            ϵ = sqrt(realtype(0.5))
+            q = if covtype == :fullrank
+                L = LowerTriangular(Matrix{realtype}(I, d, d))
+                FullRankGaussian(μ, L)
+            elseif covtype == :meanfield
+                L = Diagonal(ones(realtype, d))
+                MeanFieldGaussian(μ, L)
+            end
+            q = if isnothing(bijector)
+                q
+            else
+                Bijectors.TransformedDistribution(q, identity)
+            end
+
+            params, re = Optimisers.destructure(q)
+            params′ = AdvancedVI.operate(ClipScale(ϵ), typeof(q), params, re)
+            q′ = re(params′)
+
+            if isnothing(bijector)
+                @test all(var(q′) .≥ ϵ^2)
+            else
+                @test all(var(q′.dist) .≥ ϵ^2)
+            end
+        end
+    end
+
+    @testset "MvLocationScaleLowRank" begin
+        @testset "$(realtype) $(bijector)" for realtype in [Float32, Float64],
+            bijector in [nothing, :identity]
+
+            n_rank = 2
+            d = 5
+            μ = zeros(realtype, d)
+            ϵ = sqrt(realtype(0.5))
+            D = ones(realtype, d)
+            U = randn(realtype, d, n_rank)
+            q = MvLocationScaleLowRank(
+                μ, D, U, Normal{realtype}(zero(realtype), one(realtype))
+            )
+            q = if isnothing(bijector)
+                q
+            else
+                Bijectors.TransformedDistribution(q, bijector)
+            end
+
+            params, re = Optimisers.destructure(q)
+            params′ = AdvancedVI.operate(ClipScale(ϵ), typeof(q), params, re)
+            q′ = re(params′)
+
+            if isnothing(bijector)
+                @test all(var(q′) .≥ ϵ^2)
+            else
+                @test all(var(q′.dist) .≥ ϵ^2)
+            end
+        end
+    end
+end