add test

Author: ChrisRackauckas

test/interface/precision_mixing.jl

@@ -0,0 +1,22 @@
+using OrdinaryDiffEq
+function ODE(du, u, t, R, K)
+    du .= u
+end
+params = BigFloat[1. 0.91758707304098; 1.48439909482661 1.]
+u0 = BigFloat[0.1, 0.1]
+tspan = (1.0, 31.0)
+R = BigFloat[0.443280390004304303, 1.172917082211452]
+K = BigFloat[13.470600276901400604, 12.52980757005]
+ODE_ = (du, u, params, t) -> ODE(du, u, t, R, K)
+odeProblem = ODEProblem(ODE_, u0, tspan, params)
+for alg in [AutoVern8(Rodas5(), nonstifftol = 11 / 10)
+            FBDF()
+            QNDF()
+            Tsit5()
+            Rodas5P()
+            TRBDF2()
+            KenCarp4()
+            RadauIIA5()
+    ]
+    Solution = solve(odeProblem, alg, saveat = 1, abstol = 1.e-12, reltol = 1.e-6)
+end