diff --git a/test/src/unit-diagnostics.cpp b/test/src/unit-diagnostics.cpp
index cb09ff9439..51e756baec 100644
--- a/test/src/unit-diagnostics.cpp
+++ b/test/src/unit-diagnostics.cpp
@@ -34,7 +34,6 @@ SOFTWARE.
 #endif
 
 #define JSON_DIAGNOSTICS 1
-#define JSON_TESTS_PRIVATE
 
 #include <nlohmann/json.hpp>
 using nlohmann::json;
@@ -188,18 +187,36 @@ TEST_CASE("Better diagnostics")
 
     SECTION("Regression test for issue #3007 - Parent pointers properly set when using update()")
     {
-        json j = json::object();
-
         {
-            json j2 = json::object();
-            j2["one"] = 1;
+            // void update(const_reference j)
+            json j = json::object();
+
+            {
+                json j2 = json::object();
+                j2["one"] = 1;
+
+                j.update(j2);
+            }
 
-            j.update(j2);
+            // Must call operator[] on const element, otherwise m_parent gets updated.
+            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);
         }
 
-        for (auto const& kv : j)
         {
-            CHECK(kv.m_parent == &j);
+            // void update(const_iterator first, const_iterator last)
+            json j = json::object();
+
+            {
+                json j2 = json::object();
+                j2["one"] = 1;
+
+                j.update(j2.begin(), j2.end());
+            }
+
+            // Must call operator[] on const element, otherwise m_parent gets updated.
+            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);
         }
     }
 }