diff --git a/test/TestPlans.jl b/test/TestPlans.jl
index 6e10efe..e0d22f2 100644
--- a/test/TestPlans.jl
+++ b/test/TestPlans.jl
@@ -4,23 +4,25 @@ import AbstractFFTs
 import LinearAlgebra.mul!
 using AbstractFFTs: Plan
 
-mutable struct TestPlan{T,N} <: Plan{T}
+mutable struct TestPlan{T,N,inplace} <: Plan{T}
     region
     sz::NTuple{N,Int}
     pinv::Plan{T}
-    function TestPlan{T}(region, sz::NTuple{N,Int}) where {T,N}
-        return new{T,N}(region, sz)
+    function TestPlan{T,inplace}(region, sz::NTuple{N,Int}) where {T,N,inplace}
+        return new{T,N,inplace}(region, sz)
     end
 end
+TestPlan{T}(region, sz) where {T} = TestPlan{T,false}(region, sz)
 
-mutable struct InverseTestPlan{T,N} <: Plan{T}
+mutable struct InverseTestPlan{T,N,inplace} <: Plan{T}
     region
     sz::NTuple{N,Int}
     pinv::Plan{T}
-    function InverseTestPlan{T}(region, sz::NTuple{N,Int}) where {T,N}
-        return new{T,N}(region, sz)
+    function InverseTestPlan{T,inplace}(region, sz::NTuple{N,Int}) where {T,N,inplace}
+        return new{T,N,inplace}(region, sz)
     end
 end
+InverseTestPlan{T}(region, sz) where {T} = InverseTestPlan{T,false}(region, sz)
 
 Base.size(p::TestPlan) = p.sz
 Base.ndims(::TestPlan{T,N}) where {T,N} = N
@@ -34,18 +36,25 @@ function AbstractFFTs.plan_bfft(x::AbstractArray{T}, region; kwargs...) where {T
     return InverseTestPlan{T}(region, size(x))
 end
 
-function AbstractFFTs.plan_inv(p::TestPlan{T}) where {T}
-    unscaled_pinv = InverseTestPlan{T}(p.region, p.sz)
-    N = AbstractFFTs.normalization(T, p.sz, p.region)
-    unscaled_pinv.pinv = AbstractFFTs.ScaledPlan(p, N)
-    pinv = AbstractFFTs.ScaledPlan(unscaled_pinv, N)
+function AbstractFFTs.plan_fft!(x::AbstractArray{T}, region; kwargs...) where {T}
+    return TestPlan{T,true}(region, size(x))
+end
+function AbstractFFTs.plan_bfft!(x::AbstractArray{T}, region; kwargs...) where {T}
+    return InverseTestPlan{T,true}(region, size(x))
+end
+
+function AbstractFFTs.plan_inv(p::TestPlan{T,N,inplace}) where {T,N,inplace}
+    unscaled_pinv = InverseTestPlan{T,inplace}(p.region, p.sz)
+    _N = AbstractFFTs.normalization(T, p.sz, p.region)
+    unscaled_pinv.pinv = AbstractFFTs.ScaledPlan(p, _N)
+    pinv = AbstractFFTs.ScaledPlan(unscaled_pinv, _N)
     return pinv
 end
-function AbstractFFTs.plan_inv(pinv::InverseTestPlan{T}) where {T}
-    unscaled_p = TestPlan{T}(pinv.region, pinv.sz)
-    N = AbstractFFTs.normalization(T, pinv.sz, pinv.region)
-    unscaled_p.pinv = AbstractFFTs.ScaledPlan(pinv, N)
-    p = AbstractFFTs.ScaledPlan(unscaled_p, N)
+function AbstractFFTs.plan_inv(pinv::InverseTestPlan{T,N,inplace}) where {T,N,inplace}
+    unscaled_p = TestPlan{T,inplace}(pinv.region, pinv.sz)
+    _N = AbstractFFTs.normalization(T, pinv.sz, pinv.region)
+    unscaled_p.pinv = AbstractFFTs.ScaledPlan(pinv, _N)
+    p = AbstractFFTs.ScaledPlan(unscaled_p, _N)
     return p
 end
 
@@ -80,20 +89,23 @@ function dft!(
 end
 
 function mul!(
-    y::AbstractArray{<:Complex,N}, p::TestPlan, x::AbstractArray{<:Union{Complex,Real},N}
-) where {N}
+    y::AbstractArray{<:Complex,N}, p::TestPlan{T,N,false}, x::AbstractArray{<:Union{Complex,Real},N}
+) where {T,N}
     size(y) == size(p) == size(x) || throw(DimensionMismatch())
     dft!(y, x, p.region, -1)
 end
 function mul!(
-    y::AbstractArray{<:Complex,N}, p::InverseTestPlan, x::AbstractArray{<:Union{Complex,Real},N}
-) where {N}
+    y::AbstractArray{<:Complex,N}, p::InverseTestPlan{T,N,false}, x::AbstractArray{<:Union{Complex,Real},N}
+) where {T,N}
     size(y) == size(p) == size(x) || throw(DimensionMismatch())
     dft!(y, x, p.region, 1)
 end
 
-Base.:*(p::TestPlan, x::AbstractArray) = mul!(similar(x, complex(float(eltype(x)))), p, x)
-Base.:*(p::InverseTestPlan, x::AbstractArray) = mul!(similar(x, complex(float(eltype(x)))), p, x)
+Base.:*(p::TestPlan{T,N,false}, x::AbstractArray) where {T,N} = mul!(similar(x, complex(float(eltype(x)))), p, x)
+Base.:*(p::InverseTestPlan{T,N,false}, x::AbstractArray) where {T,N} = mul!(similar(x, complex(float(eltype(x)))), p, x)
+
+Base.:*(p::TestPlan{T,N,true}, x::AbstractArray) where {T,N} = copy!(x, dft!(similar(x), x, p.region, -1))
+Base.:*(p::InverseTestPlan{T,N,true}, x::AbstractArray) where {T,N} = copy!(x, dft!(similar(x), x, p.region, 1))
 
 mutable struct TestRPlan{T,N} <: Plan{T}
     region