Add a check that bridge is used

docs/src/submodules/Bridges/implementation.md

@@ -79,7 +79,7 @@ julia> MOI.Bridges.runtests(
            """,
        )
 Test Summary:    | Pass  Total  Time
-Bridges.runtests |   29     29  0.0s
+Bridges.runtests |   30     30  0.0s
 ```
 
 There are a number of other useful keyword arguments.
@@ -123,5 +123,5 @@ Subject to:
 ScalarAffineFunction{Int64}-in-LessThan{Int64}
  (0) - (1) x <= (-1)
 Test Summary:    | Pass  Total  Time
-Bridges.runtests |   29     29  0.0s
+Bridges.runtests |   30     30  0.0s
 ```

src/Bridges/Bridges.jl

@@ -283,7 +283,7 @@ julia> MOI.Bridges.runtests(
            end,
        )
 Test Summary:    | Pass  Total  Time
-Bridges.runtests |   32     32  0.8s
+Bridges.runtests |   33     33  0.8s
 ```
 """
 function runtests(args...; kwargs...)
@@ -303,17 +303,24 @@ function _runtests(
     model_eltype = eltype,
     print_inner_model::Bool = false,
     cannot_unbridge::Bool = false,
+    no_bridge_used::Bool = false,
 )
     # Load model and bridge it
     inner = MOI.Utilities.UniversalFallback(MOI.Utilities.Model{model_eltype}())
     model = _bridged_model(Bridge{eltype}, inner)
     input_fn(model)
+    Test.@testset "Bridge used" begin
+        _check_bridged(model; no_bridge_used)
+    end
     final_touch(model)
     # Should be able to call final_touch multiple times.
     final_touch(model)
     if print_inner_model
         print(inner)
     end
+    if no_bridge_used
+        return
+    end
     Test.@testset "Test outer bridged model appears like the input" begin       # COV_EXCL_LINE
         test =
             MOI.Utilities.UniversalFallback(MOI.Utilities.Model{model_eltype}())
@@ -437,7 +444,7 @@ julia> MOI.Bridges.runtests(
            \"\"\",
        )
 Test Summary:    | Pass  Total  Time
-Bridges.runtests |   32     32  0.0s
+Bridges.runtests |   33     33  0.0s
 ```
 """
 function runtests(
@@ -512,6 +519,15 @@ function _general_bridge_tests(bridge::B) where {B<:AbstractBridge}
     return
 end
 
+function _check_bridged(model; no_bridge_used)
+    unused =
+        isempty(MOI.Bridges.Variable.bridges(model)) &&
+        isempty(MOI.Bridges.Constraint.bridges(model)) &&
+        isempty(MOI.Bridges.Objective.bridges(model))
+    Test.@test unused == no_bridge_used
+    return
+end
+
 """
     BridgeRequiresFiniteDomainError{
         B<:AbstractBridge,

test/Bridges/Constraint/IndicatorSOS1Bridge.jl

@@ -345,6 +345,7 @@ function test_runtests()
         [z, 2.0 * x * x] in Indicator{ACTIVATE_ON_ONE}(LessThan(2.0))
         z in ZeroOne()
         """,
+        no_bridge_used = true,
     )
     return
 end

test/Bridges/Constraint/NumberConversionBridge.jl

@@ -104,6 +104,7 @@ function test_runtests()
         variables: x
         ::Float64: [x, x] in Zeros(2)
         """,
+        no_bridge_used = true,
     )
     # VectorAffineFunction
     MOI.Bridges.runtests(

test/Bridges/Objective/VectorSlackBridge.jl

@@ -103,7 +103,8 @@ function test_runtests()
         """
         variables: x
         maxobjective: [x]
-        """,
+        """;
+        no_bridge_used = true,
     )
     return
 end