Improve testing guideline

Author: blegat

docs/src/apimanual.md

@@ -576,28 +576,28 @@ The skeleton below can be used for the wrapper test file of a solver name `FooBa
 using MathOptInterface
 const MOI = MathOptInterface
 const MOIT = MOI.Test
-const MOIU = MOI.Utilities
 const MOIB = MOI.Bridges
 
-# Include here the functions/sets supported by the solver wrapper (not those that are supported through bridges)
-MOIU.@model FooBarModelData () (EqualTo, GreaterThan, LessThan) (Zeros, Nonnegatives, Nonpositives) () (SingleVariable,) (ScalarAffineFunction,) (VectorOfVariables,) (VectorAffineFunction,)
-
-MOIB.@bridge SplitInterval MOIB.SplitIntervalBridge () (Interval,) () () () (ScalarAffineFunction,) () ()
-MOIB.@bridge GeoMean MOIB.GeoMeanBridge () () (GeometricMeanCone,) () () () (VectorOfVariables,) (VectorAffineFunction,)
-MOIB.@bridge RootDet MOIB.RootDetBridge () () (RootDetConeTriangle,) () () () (VectorOfVariables,) (VectorAffineFunction,)
-
 const optimizer = FooBarOptimizer()
 const config = MOIT.TestConfig(atol=1e-6, rtol=1e-6)
 
 @testset "MOI Continuous Linear" begin
-    MOIT.contlineartest(SplitInterval{Float64}(MOIU.CachingOptimizer(FooBarModelData{Float64}(), optimizer)), config)
+    MOIT.contlineartest(MOIB.SplitInterval{Float64}(optimizer), config)
 end
 
 @testset "MOI Continuous Conic" begin
-    MOIT.contlineartest(RootDet{Float64}(GeoMean{Float64}(MOIU.CachingOptimizer(FooBarModelData{Float64}(), optimizer))), config)
+    MOIT.contlineartest(MOIB.RootDet{Float64}(MOIB.GeoMean{Float64}(optimizer)), config)
 end
 
 @testset "MOI Integer Conic" begin
-    MOIT.intconictest(MOIU.CachingOptimizer(FooBarModelData{Float64}(), optimizer), config)
+    MOIT.intconictest(optimizer, config)
 end
 ```
+
+If the wrapper does not support building the model incrementally (i.e. with `addvariable!` and `addconstraint!`), the line `const optimizer = FooBarOptimizer()` can be replaced with
+```julia
+const MOIU = MOI.Utilities
+# Include here the functions/sets supported by the solver wrapper (not those that are supported through bridges)
+MOIU.@model FooBarModelData () (EqualTo, GreaterThan, LessThan) (Zeros, Nonnegatives, Nonpositives) () (SingleVariable,) (ScalarAffineFunction,) (VectorOfVariables,) (VectorAffineFunction,)
+const optimizer = MOIU.CachingOptimizer(FooBarModelData{Float64}(), FooBarOptimizer())
+```