diff --git a/Project.toml b/Project.toml
index 5d55036..2410f48 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,6 +1,6 @@
 name = "FiniteDifferences"
 uuid = "26cc04aa-876d-5657-8c51-4c34ba976000"
-version = "0.12.15"
+version = "0.12.16"
 
 [deps]
 ChainRulesCore = "d360d2e6-b24c-11e9-a2a3-2a2ae2dbcce4"
diff --git a/src/FiniteDifferences.jl b/src/FiniteDifferences.jl
index b943030..0a44f84 100644
--- a/src/FiniteDifferences.jl
+++ b/src/FiniteDifferences.jl
@@ -9,7 +9,7 @@ using StaticArrays
 
 export to_vec, grad, jacobian, jvp, j′vp
 
-include("rand_tangent.jl")
+include("deprecated.jl")
 include("methods.jl")
 include("numerics.jl")
 include("to_vec.jl")
diff --git a/src/rand_tangent.jl b/src/deprecated.jl
similarity index 64%
rename from src/rand_tangent.jl
rename to src/deprecated.jl
index adb0ac8..cf10a91 100644
--- a/src/rand_tangent.jl
+++ b/src/deprecated.jl
@@ -1,3 +1,10 @@
+function depwarn_rt()
+    Base.depwarn(
+        "FiniteDifferences.rand_tangent is deprecated, it has moved to ChainRulesTestUtils",
+        :rand_tangent
+    )
+end
+
 """
     rand_tangent([rng::AbstractRNG,] x)
 
@@ -7,27 +14,33 @@ Rather it is an arbitary value, that is generated using the `rng`.
 """
 rand_tangent(x) = rand_tangent(Random.GLOBAL_RNG, x)
 
-rand_tangent(rng::AbstractRNG, x::Symbol) = NoTangent()
-rand_tangent(rng::AbstractRNG, x::AbstractChar) = NoTangent()
-rand_tangent(rng::AbstractRNG, x::AbstractString) = NoTangent()
+rand_tangent(rng::AbstractRNG, x::Symbol) = (depwarn_rt(); NoTangent())
+rand_tangent(rng::AbstractRNG, x::AbstractChar) = (depwarn_rt(); NoTangent())
+rand_tangent(rng::AbstractRNG, x::AbstractString) = (depwarn_rt(); NoTangent())
 
-rand_tangent(rng::AbstractRNG, x::Integer) = NoTangent()
+rand_tangent(rng::AbstractRNG, x::Integer) = (depwarn_rt(); NoTangent())
 
 # Try and make nice numbers with short decimal representations for good error messages
 # while also not biasing the sample space too much
 function rand_tangent(rng::AbstractRNG, x::T) where {T<:Number}
-    # multiply by 9 to give a bigger range of values tested: no so tightly clustered around 0.
+    depwarn_rt()
+    # multiply by 9 to give a bigger range of values tested:
+    # not so tightly clustered around 0.
     return round(9 * randn(rng, T), sigdigits=5, base=2)
 end
-rand_tangent(rng::AbstractRNG, x::Float64) = rand(rng, -9:0.01:9)
+rand_tangent(rng::AbstractRNG, x::Float64) = (depwarn_rt(); rand(rng, -9:0.01:9))
 function rand_tangent(rng::AbstractRNG, x::ComplexF64)
+    depwarn_rt()
     return ComplexF64(rand(rng, -9:0.1:9), rand(rng, -9:0.1:9))
 end
 
 #BigFloat/MPFR is finicky about short numbers, this doesn't always work as well as it should
-
-# multiply by 9 to give a bigger range of values tested: no so tightly clustered around 0.
-rand_tangent(rng::AbstractRNG, ::BigFloat) = round(big(9 * randn(rng)), sigdigits=5, base=2)
+function  rand_tangent(rng::AbstractRNG, ::BigFloat)
+    depwarn_rt()
+    # multiply by 9 to give a bigger range of values tested:
+    # not so tightly clustered around 0.
+    return round(big(9 * randn(rng)), sigdigits=5, base=2)
+end
 
 rand_tangent(rng::AbstractRNG, x::StridedArray{T, 0}) where {T} = fill(rand_tangent(x[1]))
 rand_tangent(rng::AbstractRNG, x::StridedArray) = rand_tangent.(Ref(rng), x)
@@ -53,11 +66,12 @@ function rand_tangent(rng::AbstractRNG, x::T) where {T}
     end
     if all(tangent isa NoTangent for tangent in tangents)
         # if none of my fields can be perturbed then I can't be perturbed
+        depwarn_rt()
         return NoTangent()
     else
         Tangent{T}(; NamedTuple{field_names}(tangents)...)
     end
 end
 
-rand_tangent(rng::AbstractRNG, ::Type) = NoTangent()
-rand_tangent(rng::AbstractRNG, ::Module) = NoTangent()
+rand_tangent(rng::AbstractRNG, ::Type) = (depwarn_rt(); NoTangent())
+rand_tangent(rng::AbstractRNG, ::Module) = (depwarn_rt(); NoTangent())
diff --git a/test/rand_tangent.jl b/test/deprecated.jl
similarity index 88%
rename from test/rand_tangent.jl
rename to test/deprecated.jl
index 6020286..7ca97e2 100644
--- a/test/rand_tangent.jl
+++ b/test/deprecated.jl
@@ -1,6 +1,14 @@
-using FiniteDifferences: rand_tangent
+# Test struct for `rand_tangent` and `difference`.
+struct Foo
+    a::Float64
+    b::Int
+    c::Any
+ end
 
-@testset "generate_tangent" begin
+# to avoid deprecation spam (and actually test deprecations) we will define a wrapper `rand_tangent` function for testing
+rand_tangent(args...) = @test_deprecated FiniteDifferences.rand_tangent(args...)
+
+@testset "rand_tangent" begin
     rng = MersenneTwister(123456)
 
     @testset "Primal: $(typeof(x)), Tangent: $T_tangent" for (x, T_tangent) in [
@@ -89,7 +97,9 @@ using FiniteDifferences: rand_tangent
 
     @testset "erroring cases" begin
         # Ensure struct fallback errors for non-struct types.
-        @test_throws ArgumentError invoke(rand_tangent, Tuple{AbstractRNG, Any}, rng, 5.0)
+        @test_throws ArgumentError invoke(
+            FiniteDifferences.rand_tangent, Tuple{AbstractRNG, Any}, rng, 5.0
+        )
     end
 
     @testset "compsition of addition" begin
diff --git a/test/runtests.jl b/test/runtests.jl
index eaec87c..e0b776a 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -7,17 +7,11 @@ using Random
 using StaticArrays
 using Test
 
-# Test struct for `rand_tangent` and `difference`.
-struct Foo
-   a::Float64
-   b::Int
-   c::Any
-end
 
 Random.seed!(1)
 
 @testset "FiniteDifferences" begin
-    include("rand_tangent.jl")
+    include("deprecated.jl")
     include("methods.jl")
     include("numerics.jl")
     include("to_vec.jl")