✅ Add sarima basic tests

test/models/sarima.jl

@@ -7,16 +7,26 @@
     airPassengersLog = log.(airPassengers)
 
     modeloLog = SARIMA(airPassengersLog, 3, 0, 1; seasonality=12, P=1, D=1, Q=1)
+    @test Sarimax.typeofModelElements(modeloLog) == Float64
     @test Sarimax.isFitted(modeloLog) == false
     @test getHyperparametersNumber(modeloLog) == 7
     fit!(modeloLog)
+    predict!(modeloLog; stepsAhead=10, displayConfidenceIntervals=true)
+    @test size(modeloLog.forecast,1) == 10
+    @test size(modeloLog.forecast,2) == 3
+
     @test Sarimax.isFitted(modeloLog) == true
     @test mean(modeloLog.ϵ) ≈ 0 atol=1e-1
 
     autoModelML = auto(airPassengersLog; seasonality=12 ,objectiveFunction="ml")
     @test autoModelML.d == 0 # Output of forecast package in R
     @test autoModelML.D == 1 # Output of forecast package in R
 
+    simulation = simulate(modeloLog, 10, 301)
+    @test length(simulation) == 301
+    @test length(simulation[1]) == 10
+
+
 end
 
 @testset "ARMA to MA" begin