From 9a447a9718032d7956941397dedcce3ada722cc5 Mon Sep 17 00:00:00 2001
From: Phillip Alday <me@phillipalday.com>
Date: Sat, 19 Aug 2023 17:24:32 -0500
Subject: [PATCH] better test support for Julia <1.9

---
 src/regressionmodel.jl |  3 +++
 test/delta_method.jl   | 30 +++++++++++++++++++-----------
 test/runtests.jl       |  2 +-
 3 files changed, 23 insertions(+), 12 deletions(-)

diff --git a/src/regressionmodel.jl b/src/regressionmodel.jl
index 31ab9f0..e1e8a57 100644
--- a/src/regressionmodel.jl
+++ b/src/regressionmodel.jl
@@ -147,6 +147,9 @@ end
 function _difference_method!(::Vector{T}, ::Vector{T}, 
                              ::RegressionModel, 
                              ::AutoInvLink) where {T <: AbstractFloat}
+    @static if VERSION < v"1.9"
+        @error "AutoInvLink requires extensions and is thus not available on Julia < 1.9."
+    end
     throw(ArgumentError("No appropriate extension is loaded for automatic " * 
                         "determination of the inverse link for this model type"))
 end
diff --git a/test/delta_method.jl b/test/delta_method.jl
index 417d419..6d61710 100644
--- a/test/delta_method.jl
+++ b/test/delta_method.jl
@@ -40,6 +40,8 @@ using Test
     @test isapprox(only(eff_emm_trans.upper), 47.5; atol=0.05)
 
     @testset "AutoInvLink fails gracefully" begin
+        # this should work even pre Julia 1.9 because by definition 
+        # no extension is loaded
         @test_throws ArgumentError effects(design, model; invlink=AutoInvLink())
     end
 end
@@ -52,7 +54,11 @@ end
                  :Neuroticism => [16])
     X = [1.0 13.0 16.0 13 * 16]
     iv = Base.Fix1(GLM.linkinv, Link(model.model))
-    invlinks = [iv, AutoInvLink()]
+    @static if VERSION >= v"1.9"
+        invlinks = [iv, AutoInvLink()]
+    else
+        invlinks = [iv]
+    end
     @testset "invlink = $invlink" for invlink in invlinks
         for level in [0.68, 0.95]
             eff = effects(design, model; invlink, level)
@@ -95,17 +101,19 @@ end
     end
 end
 
-@testset "link function in a MixedModel" begin
-    model = fit(MixedModel, 
-                @formula(use ~ 1 + age + (1|urban)), 
-                MixedModels.dataset(:contra), 
-                Bernoulli(); progress=false)
-    design = Dict(:age => -10:10)
-    eff_manual = effects(design, model; 
-                         invlink=Base.Fix1(GLM.linkinv, Link(model)))
-    eff_auto = effects(design, model; invlink=AutoInvLink())
+@static if VERSION >= v"1.9"
+    @testset "link function in a MixedModel" begin
+        model = fit(MixedModel, 
+                    @formula(use ~ 1 + age + (1|urban)), 
+                    MixedModels.dataset(:contra), 
+                    Bernoulli(); progress=false)
+        design = Dict(:age => -10:10)
+        eff_manual = effects(design, model; 
+                            invlink=Base.Fix1(GLM.linkinv, Link(model)))
+        eff_auto = effects(design, model; invlink=AutoInvLink())
 
-    @test all(isapprox.(Matrix(eff_manual), Matrix(eff_auto)))
+        @test all(isapprox.(Matrix(eff_manual), Matrix(eff_auto)))
+    end
 end
 
 @testset "identity by another name" begin
diff --git a/test/runtests.jl b/test/runtests.jl
index 6dbc1de..94d6117 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -3,7 +3,7 @@ using Effects
 using Test
 
 @testset "Aqua" begin
-    Aqua.test_all(Effects; ambiguities=false)
+    Aqua.test_all(Effects; ambiguities=false, project_toml_formatting)
 end
 
 @testset "TypicalTerm" begin