add tests

Author: ranocha

lib/OrdinaryDiffEqStabilizedRK/test/rkc_tests.jl

@@ -72,3 +72,33 @@ end
         @test sim.𝒪est[:l∞]≈5 atol=testTol
     end
 end
+
+@testset "Numer of function evaluations" begin
+    x = Ref(0)
+    u0 = [1.0, 1.0]
+    tspan = (0.0, 1.0)
+    probop = ODEProblem(u0, tspan) do u, p, t
+        x[] += 1
+        return -5 * u
+    end
+    probip = ODEProblem(u0, tspan) do du, u, p, t
+        x[] += 1
+        @. du = -5 * u
+        return nothing
+    end
+
+    @testset "$prob" for prob in [probop, probip]
+        eigen_est = (integrator) -> integrator.eigen_est = 5
+        algs = [ROCK2(), ROCK2(eigen_est = eigen_est),
+                ROCK4(), ROCK4(eigen_est = eigen_est),
+                RKC(),  RKC(eigen_est = eigen_est),
+                SERK2(), SERK2(eigen_est = eigen_est),
+                ESERK4(), ESERK4(eigen_est = eigen_est),
+                ESERK5(), ESERK5(eigen_est = eigen_est)]
+        @testset "$alg" for alg in algs
+            x[] = 0
+            sol = solve(prob, alg)
+            @test x[] == sol.stats.nf
+        end
+    end
+end