Make solvers silent by default

src/model.jl

@@ -193,7 +193,9 @@ function create_process_node_constraints!(model::ManufacturingModel)
     end
 end
 
-function solve(filename::String; milp_optimizer=Cbc.Optimizer, lp_optimizer=Clp.Optimizer)
+function solve(filename::String;
+               milp_optimizer=optimizer_with_attributes(Cbc.Optimizer, "logLevel" => 0),
+               lp_optimizer=optimizer_with_attributes(Clp.Optimizer, "LogLevel" => 0))
     println("Reading $filename...")
     instance = RELOG.load(filename)
     

test/model_test.jl

@@ -9,6 +9,7 @@ using RELOG, Cbc, JuMP, Printf, JSON, MathOptInterface.FileFormats
         instance = RELOG.load("$basedir/../instances/s1.json")
         graph = RELOG.build_graph(instance)
         model = RELOG.build_model(instance, graph, Cbc.Optimizer)
+        set_optimizer_attribute(model.mip, "logLevel", 0)
 
         process_node_by_location_name = Dict(n.location.location_name => n
                                              for n in graph.process_nodes)
@@ -16,7 +17,6 @@ using RELOG, Cbc, JuMP, Printf, JSON, MathOptInterface.FileFormats
         shipping_node_by_location_and_product_names = Dict((n.location.location_name, n.product.name) => n
                                                            for n in graph.plant_shipping_nodes)
         
-        
         @test length(model.vars.flow) == 76
         @test length(model.vars.dispose) == 16
         @test length(model.vars.open_plant) == 12
@@ -43,7 +43,7 @@ using RELOG, Cbc, JuMP, Printf, JSON, MathOptInterface.FileFormats
 
     @testset "solve" begin
         solution = RELOG.solve("$(pwd())/../instances/s1.json")
-        JSON.print(stdout, solution, 4)
+        #JSON.print(stdout, solution, 4)
         
         @test "Costs" in keys(solution)
         @test "Fixed operating (\$)" in keys(solution["Costs"])