test: new MovingHorizonEstimator test to improve coverage of the univariate case

Author: franckgaga

test/2_test_state_estim.jl

@@ -990,6 +990,11 @@ end
     info = getinfo(mhe5)
     @test info[:x̂] ≈ x̂ atol=1e-9
     @test info[:Ŷ][end-1:end] ≈ [50, 30] atol=1e-9
+    # for coverage of NLP functions, the univariate syntax of JuMP.@operator
+    mhe6 = MovingHorizonEstimator(nonlinmodel, He=1, Cwt=Inf)
+    setconstraint!(mhe6, v̂min=[-51,-52], v̂max=[53,54])
+    x̂ = preparestate!(mhe6, [50, 30], [5])
+    @test x̂ ≈ zeros(6) atol=1e-9
     @test_nowarn ModelPredictiveControl.info2debugstr(info)
 end