Move test_density_interface to a Test extension

.github/workflows/ci.yml

@@ -22,7 +22,7 @@ jobs:
       fail-fast: false
       matrix:
         version:
-          - '1.0'
+          - 'lts'
           - '1'
           - 'nightly'
         os:

Project.toml

@@ -4,15 +4,21 @@ version = "0.4.0"
 
 [deps]
 InverseFunctions = "3587e190-3f89-42d0-90ee-14403ec27112"
+
+[weakdeps]
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 
+[extensions]
+DensityInterfaceTestExt = "Test"
+
 [compat]
 InverseFunctions = "0.1"
-julia = "1"
+julia = "1.10"
 
 [extras]
 Documenter = "e30172f5-a6a5-5a46-863b-614d45cd2de4"
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
+Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 
 [targets]
-test = ["Documenter", "LinearAlgebra"]
+test = ["Documenter", "LinearAlgebra", "Test"]

src/interface_test.jl → ext/DensityInterfaceTestExt.jl

@@ -1,26 +1,12 @@
 # This file is a part of DensityInterface.jl, licensed under the MIT License (MIT).
 
-"""
-    DensityInterface.test_density_interface(object, x, ref_logd_at_x; kwargs...)
+module DensityInterfaceTestExt
 
-Test that `object` is compatible with `DensityInterface`.
+using Test: @test, @testset
+using DensityInterface: DensityInterface, DensityKind, IsDensity, IsOrHasDensity,
+    logdensityof, densityof, logfuncdensity, funcdensity
 
-Tests that either `DensityKind(object) isa IsOrHasDensity`.
-
-Also tests that [`logdensityof(object, x)`](@ref) equals `ref_logd_at_x` and
-that the behavior of [`logdensityof(object)`](@ref),
-[`densityof(object, x)`](@ref) and [`densityof(object)`](@ref) is consistent.
-
-The results of `logdensityof(object, x)` and `densityof(object, x)` are compared to
-`ref_logd_at_x` and `exp(ref_logd_at_x)` using `isapprox`. `kwargs...` are
-forwarded to `isapprox`.
-
-Also tests that `d = logfuncdensity(logdensityof(object))` returns a density
-(`DensityKind(d) == IsDensity()`) that is equivalent to `object` in respect to
-`logdensityof` and `densityof`, and that `funcdensity(densityof(object))`
-behaves the same way.
-"""
-function test_density_interface(object, x, ref_logd_at_x; kwargs...)
+function DensityInterface.test_density_interface(object, x, ref_logd_at_x; kwargs...)
     @testset "test_density_interface: $object with input $x" begin
         ref_d_at_x = exp(ref_logd_at_x)
 
@@ -43,3 +29,5 @@ function test_density_interface(object, x, ref_logd_at_x; kwargs...)
         end
     end
 end
+
+end # module

src/DensityInterface.jl

@@ -9,9 +9,42 @@ associated with a density.
 module DensityInterface
 
 using InverseFunctions
-using Test
 
 include("interface.jl")
-include("interface_test.jl")
+
+"""
+    DensityInterface.test_density_interface(object, x, ref_logd_at_x; kwargs...)
+
+Test that `object` is compatible with `DensityInterface`.
+
+Tests that either `DensityKind(object) isa IsOrHasDensity`.
+
+Also tests that [`logdensityof(object, x)`](@ref) equals `ref_logd_at_x` and
+that the behavior of [`logdensityof(object)`](@ref),
+[`densityof(object, x)`](@ref) and [`densityof(object)`](@ref) is consistent.
+
+The results of `logdensityof(object, x)` and `densityof(object, x)` are compared to
+`ref_logd_at_x` and `exp(ref_logd_at_x)` using `isapprox`. `kwargs...` are
+forwarded to `isapprox`.
+
+Also tests that `d = logfuncdensity(logdensityof(object))` returns a density
+(`DensityKind(d) == IsDensity()`) that is equivalent to `object` in respect to
+`logdensityof` and `densityof`, and that `funcdensity(densityof(object))`
+behaves the same way.
+
+!!! note
+    This function is available only after the `Test` standard library has been
+    loaded.
+"""
+function test_density_interface end
+
+function __init__()
+    Base.Experimental.register_error_hint(MethodError) do io, exc, _, _
+        if exc.f === test_density_interface &&
+                Base.get_extension(DensityInterface, :DensityInterfaceTestExt) === nothing
+            print(io, "\n`test_density_interface` requires the Test standard library; run `using Test` first.")
+        end
+    end
+end
 
 end # module

test/test_interface.jl

@@ -36,4 +36,16 @@ DensityInterface.logdensityof(::MyMeasure, x::Any) = -norm(x)^2
         @test DensityKind(object3) === IsDensity()
         DensityInterface.test_density_interface(object3, x, -norm(x)^2)
     end
+
+    # Needs a process that has not loaded Test
+    code = """
+        using DensityInterface
+        try
+            DensityInterface.test_density_interface(1, 1, 1)
+        catch e
+            showerror(stdout, e)
+        end
+        """
+    cmd = `$(Base.julia_cmd()) --startup-file=no --project=$(Base.active_project()) -e $code`
+    @test occursin("run `using Test` first", read(cmd, String))
 end