diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 3d8bceb70..e5484fc73 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -110,6 +110,7 @@ set(files
     src/unit-convenience.cpp
     src/unit-conversions.cpp
     src/unit-deserialization.cpp
+    src/unit-diagnostics.cpp
     src/unit-element_access1.cpp
     src/unit-element_access2.cpp
     src/unit-hash.cpp
diff --git a/test/src/unit-diagnostics.cpp b/test/src/unit-diagnostics.cpp
new file mode 100644
index 000000000..d7c8e772b
--- /dev/null
+++ b/test/src/unit-diagnostics.cpp
@@ -0,0 +1,81 @@
+/*
+    __ _____ _____ _____
+ __|  |   __|     |   | |  JSON for Modern C++ (test suite)
+|  |  |__   |  |  | | | |  version 3.9.1
+|_____|_____|_____|_|___|  https://github.com/nlohmann/json
+
+Licensed under the MIT License <http://opensource.org/licenses/MIT>.
+SPDX-License-Identifier: MIT
+Copyright (c) 2013-2019 Niels Lohmann <http://nlohmann.me>.
+
+Permission is hereby  granted, free of charge, to any  person obtaining a copy
+of this software and associated  documentation files (the "Software"), to deal
+in the Software  without restriction, including without  limitation the rights
+to  use, copy,  modify, merge,  publish, distribute,  sublicense, and/or  sell
+copies  of  the Software,  and  to  permit persons  to  whom  the Software  is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE  IS PROVIDED "AS  IS", WITHOUT WARRANTY  OF ANY KIND,  EXPRESS OR
+IMPLIED,  INCLUDING BUT  NOT  LIMITED TO  THE  WARRANTIES OF  MERCHANTABILITY,
+FITNESS FOR  A PARTICULAR PURPOSE AND  NONINFRINGEMENT. IN NO EVENT  SHALL THE
+AUTHORS  OR COPYRIGHT  HOLDERS  BE  LIABLE FOR  ANY  CLAIM,  DAMAGES OR  OTHER
+LIABILITY, WHETHER IN AN ACTION OF  CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE  OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+*/
+
+#include "doctest_compatibility.h"
+
+#define JSON_DIAGNOSTICS 1
+#include <nlohmann/json.hpp>
+using nlohmann::json;
+
+TEST_CASE("Better diagnostics")
+{
+    SECTION("invalid type")
+    {
+        json j;
+        j["a"]["b"]["c"] = 1;
+        std::string s;
+        CHECK_THROWS_WITH_AS(s = j["a"]["b"]["c"], "[json.exception.type_error.302] (/a/b/c) type must be string, but is number", json::type_error);
+    }
+
+    SECTION("missing key")
+    {
+        json j;
+        j["object"]["object"] = true;
+        CHECK_THROWS_WITH_AS(j["object"].at("not_found"), "[json.exception.out_of_range.403] (/object) key 'not_found' not found", json::out_of_range);
+    }
+
+    SECTION("array index out of range")
+    {
+        json j;
+        j["array"][4] = true;
+        CHECK_THROWS_WITH_AS(j["array"].at(5), "[json.exception.out_of_range.401] (/array) array index 5 is out of range", json::out_of_range);
+    }
+
+    SECTION("array index at wrong type")
+    {
+        json j;
+        j["array"][4] = true;
+        CHECK_THROWS_WITH_AS(j["array"][4][5], "[json.exception.type_error.305] (/array/4) cannot use operator[] with a numeric argument with boolean", json::type_error);
+    }
+
+    SECTION("wrong iterator")
+    {
+        json j;
+        j["array"] = json::array();
+        CHECK_THROWS_WITH_AS(j["array"].erase(j.begin()), "[json.exception.invalid_iterator.202] (/array) iterator does not fit current value", json::invalid_iterator);
+    }
+
+    SECTION("JSON Pointer escaping")
+    {
+        json j;
+        j["a/b"]["m~n"] = 1;
+        std::string s;
+        CHECK_THROWS_WITH_AS(s = j["a/b"]["m~n"], "[json.exception.type_error.302] (/a~1b/m~0n) type must be string, but is number", json::type_error);
+    }
+}
diff --git a/test/src/unit-unicode.cpp b/test/src/unit-unicode.cpp
index acaca2888..654c48c2a 100644
--- a/test/src/unit-unicode.cpp
+++ b/test/src/unit-unicode.cpp
@@ -1181,8 +1181,8 @@ TEST_CASE("Unicode" * doctest::skip())
                 CHECK_NOTHROW(json::json_pointer("/" + ptr));
 
                 // check escape/unescape roundtrip
-                auto escaped = json::json_pointer::escape(ptr);
-                json::json_pointer::unescape(escaped);
+                auto escaped = nlohmann::detail::escape(ptr);
+                nlohmann::detail::unescape(escaped);
                 CHECK(escaped == ptr);
             }
         }