Add solve_time function (#1928)

* added ProxSDP to solvers list

* added low accuracy commentary

* Added solve_time function

* typo fix

* better error message

* removing _try_get_solve_time

* added solve_time to docs

docs/src/solutions.md

@@ -127,6 +127,7 @@ JuMP.value
 JuMP.dual_status
 JuMP.has_duals
 JuMP.dual
+JuMP.solve_time
 OptimizeNotCalled
 MOI.optimize!
 ```

src/JuMP.jl

@@ -438,6 +438,18 @@ end
 
 set_optimize_hook(model::Model, f) = (model.optimize_hook = f)
 
+"""
+    solve_time(model::Model)
+
+If available, returns the solve time reported by the solver.
+Returns "ArgumentError: ModelLike of type `Solver.Optimizer` does not support accessing
+the attribute MathOptInterface.SolveTime()" if the attribute is
+not implemented.
+"""
+function solve_time(model::Model)
+    return MOI.get(model, MOI.SolveTime())
+end
+
 """
     set_silent(model::Model)
 

test/model.jl

@@ -328,6 +328,25 @@ function test_model()
         @test optimizer.b == 2
     end
 
+    @testset "solve_time" begin
+        @testset "NoOptimizer()" begin
+            err = NoOptimizer()
+            model = Model()
+            @test_throws err solve_time(model)
+        end
+
+        @testset "OptimizeNotCalled()" begin
+            err = OptimizeNotCalled()
+            model = Model(with_optimizer(MOIU.MockOptimizer,
+                                         SimpleLPModel{Float64}()))
+            @test_throws err solve_time(model)
+        end
+
+        @testset "Solved model" begin
+            # TODO
+        end
+    end
+
     @testset "solver_name" begin
         @testset "Not attached" begin
             model = Model()