diff --git a/test/src/unit-diagnostics.cpp b/test/src/unit-diagnostics.cpp
index 51e756bae..8e4f2ffc3 100644
--- a/test/src/unit-diagnostics.cpp
+++ b/test/src/unit-diagnostics.cpp
@@ -187,8 +187,8 @@ TEST_CASE("Better diagnostics")
 
     SECTION("Regression test for issue #3007 - Parent pointers properly set when using update()")
     {
+        // void update(const_reference j)
         {
-            // void update(const_reference j)
             json j = json::object();
 
             {
@@ -203,8 +203,8 @@ TEST_CASE("Better diagnostics")
             CHECK_THROWS_WITH_AS(constJ["one"].at(0), "[json.exception.type_error.304] (/one) cannot use at() with number", json::type_error);
         }
 
+        // void update(const_iterator first, const_iterator last)
         {
-            // void update(const_iterator first, const_iterator last)
             json j = json::object();
 
             {
@@ -218,5 +218,20 @@ TEST_CASE("Better diagnostics")
             auto const& constJ = j;
             CHECK_THROWS_WITH_AS(constJ["one"].at(0), "[json.exception.type_error.304] (/one) cannot use at() with number", json::type_error);
         }
+
+        // Code from #3007 triggering unwanted assertion without fix to update().
+        {
+            json root = json::array();
+            json lower = json::object();
+
+            {
+                json lowest = json::object();
+                lowest["one"] = 1;
+
+                lower.update(lowest);
+            }
+
+            root.push_back(lower);
+        }
     }
 }