From 736b4a36ee75e5566fce3a98c3a3bd0b8789e97d Mon Sep 17 00:00:00 2001
From: Avik Pal <avikpal@mit.edu>
Date: Fri, 27 Sep 2024 15:29:07 -0400
Subject: [PATCH] test: issue 451

---
 test/misc/issues_tests.jl | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)
 create mode 100644 test/misc/issues_tests.jl

diff --git a/test/misc/issues_tests.jl b/test/misc/issues_tests.jl
new file mode 100644
index 000000000..24e39943c
--- /dev/null
+++ b/test/misc/issues_tests.jl
@@ -0,0 +1,22 @@
+@testitem "Issue #451" tags=[:misc] begin
+    f(u, p) = u^2 - p
+
+    jac_calls = 0
+    function df(u, p)
+        global jac_calls += 1
+        return 2u
+    end
+
+    fn = NonlinearFunction(f; jac = df)
+    prob = NonlinearProblem(fn, 1.0, 2.0)
+    sol = solve(prob, NewtonRaphson())
+    @test sol.retcode == ReturnCode.Success
+    @test jac_calls ≥ 1
+
+    jac_calls = 0
+    fn2 = NonlinearFunction(f)
+    prob = NonlinearProblem(fn2, 1.0, 2.0)
+    sol = solve(prob, NewtonRaphson())
+    @test sol.retcode == ReturnCode.Success
+    @test jac_calls == 0
+end