diff --git a/include/nlohmann/detail/json_pointer.hpp b/include/nlohmann/detail/json_pointer.hpp
index 4fdcd9ad2..cef2e0686 100644
--- a/include/nlohmann/detail/json_pointer.hpp
+++ b/include/nlohmann/detail/json_pointer.hpp
@@ -71,7 +71,7 @@ class json_pointer
                                string_t{},
                                [](const string_t& a, const string_t& b)
         {
-            return detail::concat(a, '/', detail::escape(b));
+            return detail::concat<string_t>(a, '/', detail::escape(b));
         });
     }
 
diff --git a/include/nlohmann/json.hpp b/include/nlohmann/json.hpp
index 95d6bf1dd..808a90782 100644
--- a/include/nlohmann/json.hpp
+++ b/include/nlohmann/json.hpp
@@ -4702,7 +4702,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         // the valid JSON Patch operations
         enum class patch_operations {add, remove, replace, move, copy, test, invalid};
 
-        const auto get_op = [](const std::string & op)
+        const auto get_op = [](const StringType & op)
         {
             if (op == "add")
             {
@@ -4839,8 +4839,8 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         for (const auto& val : json_patch)
         {
             // wrapper to get a value for an operation
-            const auto get_value = [&val](const std::string & op,
-                                          const std::string & member,
+            const auto get_value = [&val](const StringType & op,
+                                          const StringType & member,
                                           bool string_type) -> basic_json &
             {
                 // find value
@@ -4874,8 +4874,8 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
             }
 
             // collect mandatory members
-            const auto op = get_value("op", "op", true).template get<std::string>();
-            const auto path = get_value(op, "path", true).template get<std::string>();
+            const auto op = get_value("op", "op", true).template get<StringType>();
+            const auto path = get_value(op, "path", true).template get<StringType>();
             json_pointer ptr(path);
 
             switch (get_op(op))
@@ -4901,7 +4901,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
 
                 case patch_operations::move:
                 {
-                    const auto from_path = get_value("move", "from", true).template get<std::string>();
+                    const auto from_path = get_value("move", "from", true).template get<StringType>();
                     json_pointer from_ptr(from_path);
 
                     // the "from" location must exist - use at()
@@ -4918,7 +4918,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
 
                 case patch_operations::copy:
                 {
-                    const auto from_path = get_value("copy", "from", true).template get<std::string>();
+                    const auto from_path = get_value("copy", "from", true).template get<StringType>();
                     const json_pointer from_ptr(from_path);
 
                     // the "from" location must exist - use at()
@@ -4978,7 +4978,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
     /// @sa https://json.nlohmann.me/api/basic_json/diff/
     JSON_HEDLEY_WARN_UNUSED_RESULT
     static basic_json diff(const basic_json& source, const basic_json& target,
-                           const std::string& path = "")
+                           const StringType& path = "")
     {
         // the patch
         basic_json result(value_t::array);
@@ -5007,8 +5007,14 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
                 std::size_t i = 0;
                 while (i < source.size() && i < target.size())
                 {
+                    StringType array_index_str;
+                    {
+                        using namespace detail;
+                        int_to_string(array_index_str, i);
+                    }
+
                     // recursive call to compare array values at index i
-                    auto temp_diff = diff(source[i], target[i], detail::concat(path, '/', std::to_string(i)));
+                    auto temp_diff = diff(source[i], target[i], detail::concat<StringType>(path, '/', array_index_str));
                     result.insert(result.end(), temp_diff.begin(), temp_diff.end());
                     ++i;
                 }
@@ -5022,10 +5028,17 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
                 {
                     // add operations in reverse order to avoid invalid
                     // indices
+
+                    StringType array_index_str;
+                    {
+                        using namespace detail;
+                        int_to_string(array_index_str, i);
+                    }
+
                     result.insert(result.begin() + end_index, object(
                     {
                         {"op", "remove"},
-                        {"path", detail::concat(path, '/', std::to_string(i))}
+                        {"path", detail::concat<StringType>(path, '/', array_index_str)}
                     }));
                     ++i;
                 }
@@ -5036,7 +5049,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
                     result.push_back(
                     {
                         {"op", "add"},
-                        {"path", detail::concat(path, "/-")},
+                        {"path", detail::concat<StringType>(path, "/-")},
                         {"value", target[i]}
                     });
                     ++i;
@@ -5051,7 +5064,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
                 for (auto it = source.cbegin(); it != source.cend(); ++it)
                 {
                     // escape the key name to be used in a JSON patch
-                    const auto path_key = detail::concat(path, '/', detail::escape(it.key()));
+                    const auto path_key = detail::concat<StringType>(path, '/', detail::escape(it.key()));
 
                     if (target.find(it.key()) != target.end())
                     {
@@ -5075,7 +5088,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
                     if (source.find(it.key()) == source.end())
                     {
                         // found a key that is not in this -> add it
-                        const auto path_key = detail::concat(path, '/', detail::escape(it.key()));
+                        const auto path_key = detail::concat<StringType>(path, '/', detail::escape(it.key()));
                         result.push_back(
                         {
                             {"op", "add"}, {"path", path_key},
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index b191bb914..8314729ce 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -41,7 +41,6 @@
 // SPDX-License-Identifier: MIT
 
 
-
 #include <utility>
 
 // #include <nlohmann/detail/abi_macros.hpp>
@@ -54,7 +53,6 @@
 // SPDX-License-Identifier: MIT
 
 
-
 // This file contains all macro definitions affecting or depending on the ABI
 
 #ifndef JSON_SKIP_LIBRARY_VERSION_CHECK
@@ -156,7 +154,6 @@
 // SPDX-License-Identifier: MIT
 
 
-
 #include <algorithm> // transform
 #include <array> // array
 #include <forward_list> // forward_list
@@ -179,7 +176,6 @@
 // SPDX-License-Identifier: MIT
 
 
-
 #include <cstddef> // nullptr_t
 #include <exception> // exception
 #if JSON_DIAGNOSTICS
@@ -199,7 +195,6 @@
 // SPDX-License-Identifier: MIT
 
 
-
 #include <array> // array
 #include <cstddef> // size_t
 #include <cstdint> // uint8_t
@@ -215,7 +210,6 @@
 // SPDX-License-Identifier: MIT
 
 
-
 #include <utility> // declval, pair
 // #include <nlohmann/detail/meta/detected.hpp>
 //     __ _____ _____ _____
@@ -227,7 +221,6 @@
 // SPDX-License-Identifier: MIT
 
 
-
 #include <type_traits>
 
 // #include <nlohmann/detail/meta/void_t.hpp>
@@ -240,7 +233,6 @@
 // SPDX-License-Identifier: MIT
 
 
-
 // #include <nlohmann/detail/abi_macros.hpp>
 
 
@@ -2946,7 +2938,6 @@ NLOHMANN_JSON_NAMESPACE_END
 // SPDX-License-Identifier: MIT
 
 
-
 // #include <nlohmann/detail/abi_macros.hpp>
 
 
@@ -3021,7 +3012,6 @@ NLOHMANN_JSON_NAMESPACE_END
 // SPDX-License-Identifier: MIT
 
 
-
 #include <cstddef> // size_t
 
 // #include <nlohmann/detail/abi_macros.hpp>
@@ -3064,7 +3054,6 @@ NLOHMANN_JSON_NAMESPACE_END
 // SPDX-License-Identifier: MIT
 
 
-
 #include <array> // array
 #include <cstddef> // size_t
 #include <type_traits> // conditional, enable_if, false_type, integral_constant, is_constructible, is_integral, is_same, remove_cv, remove_reference, true_type
@@ -3237,7 +3226,6 @@ NLOHMANN_JSON_NAMESPACE_END
 // SPDX-License-Identifier: MIT
 
 
-
 #include <limits> // numeric_limits
 #include <type_traits> // false_type, is_constructible, is_integral, is_same, true_type
 #include <utility> // declval
@@ -3254,7 +3242,6 @@ NLOHMANN_JSON_NAMESPACE_END
 // SPDX-License-Identifier: MIT
 
 
-
 #include <iterator> // random_access_iterator_tag
 
 // #include <nlohmann/detail/abi_macros.hpp>
@@ -3322,7 +3309,6 @@ NLOHMANN_JSON_NAMESPACE_END
 // SPDX-License-Identifier: MIT
 
 
-
 // #include <nlohmann/detail/macro_scope.hpp>
 
 
@@ -3342,7 +3328,6 @@ NLOHMANN_JSON_NAMESPACE_END
 // SPDX-License-Identifier: MIT
 
 
-
 // #include <nlohmann/detail/macro_scope.hpp>
 
 
@@ -4217,7 +4202,6 @@ NLOHMANN_JSON_NAMESPACE_END
 // SPDX-License-Identifier: MIT
 
 
-
 #include <cstring> // strlen
 #include <string> // string
 #include <utility> // forward
@@ -4603,7 +4587,6 @@ NLOHMANN_JSON_NAMESPACE_END
 // SPDX-License-Identifier: MIT
 
 
-
 // #include <nlohmann/detail/abi_macros.hpp>
 
 
@@ -4627,7 +4610,6 @@ NLOHMANN_JSON_NAMESPACE_END
 // SPDX-License-Identifier: MIT
 
 
-
 // #include <nlohmann/detail/macro_scope.hpp>
 
 
@@ -5133,7 +5115,6 @@ NLOHMANN_JSON_NAMESPACE_END
 // SPDX-License-Identifier: MIT
 
 
-
 #include <algorithm> // copy
 #include <iterator> // begin, end
 #include <string> // string
@@ -5153,7 +5134,6 @@ NLOHMANN_JSON_NAMESPACE_END
 // SPDX-License-Identifier: MIT
 
 
-
 #include <cstddef> // size_t
 #include <iterator> // input_iterator_tag
 #include <string> // string, to_string
@@ -5875,7 +5855,6 @@ NLOHMANN_JSON_NAMESPACE_END
 // SPDX-License-Identifier: MIT
 
 
-
 #include <cstdint> // uint8_t, uint64_t
 #include <tuple> // tie
 #include <utility> // move
@@ -5987,7 +5966,6 @@ NLOHMANN_JSON_NAMESPACE_END
 // SPDX-License-Identifier: MIT
 
 
-
 #include <cstdint> // uint8_t
 #include <cstddef> // size_t
 #include <functional> // hash
@@ -6120,7 +6098,6 @@ NLOHMANN_JSON_NAMESPACE_END
 // SPDX-License-Identifier: MIT
 
 
-
 #include <algorithm> // generate_n
 #include <array> // array
 #include <cmath> // ldexp
@@ -6146,7 +6123,6 @@ NLOHMANN_JSON_NAMESPACE_END
 // SPDX-License-Identifier: MIT
 
 
-
 #include <array> // array
 #include <cstddef> // size_t
 #include <cstring> // strlen
@@ -6643,7 +6619,6 @@ NLOHMANN_JSON_NAMESPACE_END
 // SPDX-License-Identifier: MIT
 
 
-
 #include <cstddef>
 #include <string> // string
 #include <utility> // move
@@ -7375,7 +7350,6 @@ NLOHMANN_JSON_NAMESPACE_END
 // SPDX-License-Identifier: MIT
 
 
-
 #include <array> // array
 #include <clocale> // localeconv
 #include <cstddef> // size_t
@@ -9016,7 +8990,6 @@ NLOHMANN_JSON_NAMESPACE_END
 // SPDX-License-Identifier: MIT
 
 
-
 #include <cstdint> // size_t
 #include <utility> // declval
 #include <string> // string
@@ -12168,7 +12141,6 @@ NLOHMANN_JSON_NAMESPACE_END
 // SPDX-License-Identifier: MIT
 
 
-
 #include <cmath> // isfinite
 #include <cstdint> // uint8_t
 #include <functional> // function
@@ -12697,7 +12669,6 @@ NLOHMANN_JSON_NAMESPACE_END
 // SPDX-License-Identifier: MIT
 
 
-
 // #include <nlohmann/detail/abi_macros.hpp>
 
 // #include <nlohmann/detail/iterators/primitive_iterator.hpp>
@@ -12710,7 +12681,6 @@ NLOHMANN_JSON_NAMESPACE_END
 // SPDX-License-Identifier: MIT
 
 
-
 #include <cstddef> // ptrdiff_t
 #include <limits>  // numeric_limits
 
@@ -12869,7 +12839,6 @@ NLOHMANN_JSON_NAMESPACE_END
 // SPDX-License-Identifier: MIT
 
 
-
 #include <iterator> // iterator, random_access_iterator_tag, bidirectional_iterator_tag, advance, next
 #include <type_traits> // conditional, is_const, remove_const
 
@@ -13631,7 +13600,6 @@ NLOHMANN_JSON_NAMESPACE_END
 // SPDX-License-Identifier: MIT
 
 
-
 #include <cstddef> // ptrdiff_t
 #include <iterator> // reverse_iterator
 #include <utility> // declval
@@ -13808,7 +13776,6 @@ NLOHMANN_JSON_NAMESPACE_END
 // SPDX-License-Identifier: MIT
 
 
-
 #include <algorithm> // all_of
 #include <cctype> // isdigit
 #include <cerrno> // errno, ERANGE
@@ -13877,7 +13844,7 @@ class json_pointer
                                string_t{},
                                [](const string_t& a, const string_t& b)
         {
-            return detail::concat(a, '/', detail::escape(b));
+            return detail::concat<string_t>(a, '/', detail::escape(b));
         });
     }
 
@@ -14803,7 +14770,6 @@ NLOHMANN_JSON_NAMESPACE_END
 // SPDX-License-Identifier: MIT
 
 
-
 #include <initializer_list>
 #include <utility>
 
@@ -14895,7 +14861,6 @@ NLOHMANN_JSON_NAMESPACE_END
 // SPDX-License-Identifier: MIT
 
 
-
 #include <algorithm> // reverse
 #include <array> // array
 #include <map> // map
@@ -14921,7 +14886,6 @@ NLOHMANN_JSON_NAMESPACE_END
 // SPDX-License-Identifier: MIT
 
 
-
 #include <algorithm> // copy
 #include <cstddef> // size_t
 #include <iterator> // back_inserter
@@ -16890,7 +16854,6 @@ NLOHMANN_JSON_NAMESPACE_END
 // SPDX-License-Identifier: MIT
 
 
-
 #include <algorithm> // reverse, remove, fill, find, none_of
 #include <array> // array
 #include <clocale> // localeconv, lconv
@@ -16915,7 +16878,6 @@ NLOHMANN_JSON_NAMESPACE_END
 // SPDX-License-Identifier: MIT
 
 
-
 #include <array> // array
 #include <cmath>   // signbit, isfinite
 #include <cstdint> // intN_t, uintN_t
@@ -19010,7 +18972,6 @@ NLOHMANN_JSON_NAMESPACE_END
 // SPDX-License-Identifier: MIT
 
 
-
 #include <functional> // equal_to, less
 #include <initializer_list> // initializer_list
 #include <iterator> // input_iterator_tag, iterator_traits
@@ -24005,7 +23966,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         // the valid JSON Patch operations
         enum class patch_operations {add, remove, replace, move, copy, test, invalid};
 
-        const auto get_op = [](const std::string & op)
+        const auto get_op = [](const StringType & op)
         {
             if (op == "add")
             {
@@ -24142,8 +24103,8 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         for (const auto& val : json_patch)
         {
             // wrapper to get a value for an operation
-            const auto get_value = [&val](const std::string & op,
-                                          const std::string & member,
+            const auto get_value = [&val](const StringType & op,
+                                          const StringType & member,
                                           bool string_type) -> basic_json &
             {
                 // find value
@@ -24177,8 +24138,8 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
             }
 
             // collect mandatory members
-            const auto op = get_value("op", "op", true).template get<std::string>();
-            const auto path = get_value(op, "path", true).template get<std::string>();
+            const auto op = get_value("op", "op", true).template get<StringType>();
+            const auto path = get_value(op, "path", true).template get<StringType>();
             json_pointer ptr(path);
 
             switch (get_op(op))
@@ -24204,7 +24165,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
 
                 case patch_operations::move:
                 {
-                    const auto from_path = get_value("move", "from", true).template get<std::string>();
+                    const auto from_path = get_value("move", "from", true).template get<StringType>();
                     json_pointer from_ptr(from_path);
 
                     // the "from" location must exist - use at()
@@ -24221,7 +24182,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
 
                 case patch_operations::copy:
                 {
-                    const auto from_path = get_value("copy", "from", true).template get<std::string>();
+                    const auto from_path = get_value("copy", "from", true).template get<StringType>();
                     const json_pointer from_ptr(from_path);
 
                     // the "from" location must exist - use at()
@@ -24281,7 +24242,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
     /// @sa https://json.nlohmann.me/api/basic_json/diff/
     JSON_HEDLEY_WARN_UNUSED_RESULT
     static basic_json diff(const basic_json& source, const basic_json& target,
-                           const std::string& path = "")
+                           const StringType& path = "")
     {
         // the patch
         basic_json result(value_t::array);
@@ -24310,8 +24271,14 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
                 std::size_t i = 0;
                 while (i < source.size() && i < target.size())
                 {
+                    StringType array_index_str;
+                    {
+                        using namespace detail;
+                        int_to_string(array_index_str, i);
+                    }
+
                     // recursive call to compare array values at index i
-                    auto temp_diff = diff(source[i], target[i], detail::concat(path, '/', std::to_string(i)));
+                    auto temp_diff = diff(source[i], target[i], detail::concat<StringType>(path, '/', array_index_str));
                     result.insert(result.end(), temp_diff.begin(), temp_diff.end());
                     ++i;
                 }
@@ -24325,10 +24292,17 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
                 {
                     // add operations in reverse order to avoid invalid
                     // indices
+
+                    StringType array_index_str;
+                    {
+                        using namespace detail;
+                        int_to_string(array_index_str, i);
+                    }
+
                     result.insert(result.begin() + end_index, object(
                     {
                         {"op", "remove"},
-                        {"path", detail::concat(path, '/', std::to_string(i))}
+                        {"path", detail::concat<StringType>(path, '/', array_index_str)}
                     }));
                     ++i;
                 }
@@ -24339,7 +24313,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
                     result.push_back(
                     {
                         {"op", "add"},
-                        {"path", detail::concat(path, "/-")},
+                        {"path", detail::concat<StringType>(path, "/-")},
                         {"value", target[i]}
                     });
                     ++i;
@@ -24354,7 +24328,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
                 for (auto it = source.cbegin(); it != source.cend(); ++it)
                 {
                     // escape the key name to be used in a JSON patch
-                    const auto path_key = detail::concat(path, '/', detail::escape(it.key()));
+                    const auto path_key = detail::concat<StringType>(path, '/', detail::escape(it.key()));
 
                     if (target.find(it.key()) != target.end())
                     {
@@ -24378,7 +24352,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
                     if (source.find(it.key()) == source.end())
                     {
                         // found a key that is not in this -> add it
-                        const auto path_key = detail::concat(path, '/', detail::escape(it.key()));
+                        const auto path_key = detail::concat<StringType>(path, '/', detail::escape(it.key()));
                         result.push_back(
                         {
                             {"op", "add"}, {"path", path_key},
@@ -24566,7 +24540,6 @@ inline void swap(nlohmann::NLOHMANN_BASIC_JSON_TPL& j1, nlohmann::NLOHMANN_BASIC
 // SPDX-License-Identifier: MIT
 
 
-
 // restore clang diagnostic settings
 #if defined(__clang__)
     #pragma clang diagnostic pop
@@ -24611,7 +24584,6 @@ inline void swap(nlohmann::NLOHMANN_BASIC_JSON_TPL& j1, nlohmann::NLOHMANN_BASIC
 // SPDX-License-Identifier: MIT
 
 
-
 #undef JSON_HEDLEY_ALWAYS_INLINE
 #undef JSON_HEDLEY_ARM_VERSION
 #undef JSON_HEDLEY_ARM_VERSION_CHECK
@@ -24762,5 +24734,4 @@ inline void swap(nlohmann::NLOHMANN_BASIC_JSON_TPL& j1, nlohmann::NLOHMANN_BASIC
 #undef JSON_HEDLEY_FALL_THROUGH
 
 
-
 #endif  // INCLUDE_NLOHMANN_JSON_HPP_
diff --git a/single_include/nlohmann/json_fwd.hpp b/single_include/nlohmann/json_fwd.hpp
index 29a6036d7..f219db3be 100644
--- a/single_include/nlohmann/json_fwd.hpp
+++ b/single_include/nlohmann/json_fwd.hpp
@@ -25,7 +25,6 @@
 // SPDX-License-Identifier: MIT
 
 
-
 // This file contains all macro definitions affecting or depending on the ABI
 
 #ifndef JSON_SKIP_LIBRARY_VERSION_CHECK
diff --git a/tests/src/unit-alt-string.cpp b/tests/src/unit-alt-string.cpp
index 7efe2e2e9..faa49d3d4 100644
--- a/tests/src/unit-alt-string.cpp
+++ b/tests/src/unit-alt-string.cpp
@@ -35,10 +35,33 @@ class alt_string
     alt_string(size_t count, char chr): str_impl(count, chr) {}
     alt_string() = default;
 
-    template <typename...TParams>
-    alt_string& append(TParams&& ...params)
+    alt_string& append(std::size_t count, char ch)
     {
-        str_impl.append(std::forward<TParams>(params)...);
+        str_impl.append(count, ch);
+        return *this;
+    }
+
+    alt_string& append(const alt_string& str)
+    {
+        str_impl.append(str.str_impl);
+        return *this;
+    }
+
+    alt_string& append(const char* s, std::size_t count)
+    {
+        str_impl.append(s, count);
+        return *this;
+    }
+
+    alt_string& append(const char* s)
+    {
+        str_impl.append(s);
+        return *this;
+    }
+
+    alt_string& operator+=(char ch)
+    {
+        str_impl += ch;
         return *this;
     }
 
@@ -74,6 +97,11 @@ class alt_string
         return str_impl.size();
     }
 
+    void reserve (std::size_t n)
+    {
+        str_impl.reserve(n);
+    }
+
     void resize (std::size_t n)
     {
         str_impl.resize(n);
@@ -318,5 +346,18 @@ TEST_CASE("alternative string type")
 
         CHECK(j.at(alt_json::json_pointer("/foo/0")) == j["foo"][0]);
         CHECK(j.at(alt_json::json_pointer("/foo/1")) == j["foo"][1]);
+
+        // ensures successful compilation
+        CHECK(alt_json::json_pointer("/foo/0").to_string() == "/foo/0");
+    }
+
+    SECTION("JSON patch")
+    {
+        // for now, just ensures successful compilation (see #4134)
+        alt_json base, target;
+        alt_json patch = alt_json::array();
+
+        base.patch(patch);
+        CHECK_NOTHROW(alt_json::diff(target, base));
     }
 }
diff --git a/tests/src/unit-bjdata.cpp b/tests/src/unit-bjdata.cpp
index 9f247fe6f..7fdfd547d 100644
--- a/tests/src/unit-bjdata.cpp
+++ b/tests/src/unit-bjdata.cpp
@@ -339,13 +339,13 @@ TEST_CASE("BJData")
                     std::vector<int32_t> const numbers
                     {
                         -32769,
-                            -100000,
-                            -1000000,
-                            -10000000,
-                            -100000000,
-                            -1000000000,
-                            -2147483647 - 1, // https://stackoverflow.com/a/29356002/266378
-                        };
+                        -100000,
+                        -1000000,
+                        -10000000,
+                        -100000000,
+                        -1000000000,
+                        -2147483647 - 1, // https://stackoverflow.com/a/29356002/266378
+                    };
                     for (const auto i : numbers)
                     {
                         CAPTURE(i)
diff --git a/tests/src/unit-cbor.cpp b/tests/src/unit-cbor.cpp
index be94d2f6e..332386471 100644
--- a/tests/src/unit-cbor.cpp
+++ b/tests/src/unit-cbor.cpp
@@ -241,13 +241,13 @@ TEST_CASE("CBOR")
                     const std::vector<int64_t> numbers
                     {
                         -65537,
-                            -100000,
-                            -1000000,
-                            -10000000,
-                            -100000000,
-                            -1000000000,
-                            -4294967296,
-                        };
+                        -100000,
+                        -1000000,
+                        -10000000,
+                        -100000000,
+                        -1000000000,
+                        -4294967296,
+                    };
                     for (const auto i : numbers)
                     {
                         CAPTURE(i)
diff --git a/tests/src/unit-msgpack.cpp b/tests/src/unit-msgpack.cpp
index 61162afae..e598adc68 100644
--- a/tests/src/unit-msgpack.cpp
+++ b/tests/src/unit-msgpack.cpp
@@ -479,11 +479,11 @@ TEST_CASE("MessagePack")
                     std::vector<int32_t> const numbers
                     {
                         -32769,
-                            -65536,
-                            -77777,
-                            -1048576,
-                            -2147483648LL,
-                        };
+                        -65536,
+                        -77777,
+                        -1048576,
+                        -2147483648LL,
+                    };
                     for (auto i : numbers)
                     {
                         CAPTURE(i)