1 files changed, 130 insertions, 0 deletions
diff --git a/json4cpp/tests/src/unit-user_defined_input.cpp b/json4cpp/tests/src/unit-user_defined_input.cpp
new file mode 100644
index 0000000000..56446ea94c
--- /dev/null
+++ b/json4cpp/tests/src/unit-user_defined_input.cpp
@@ -0,0 +1,130 @@
+//     __ _____ _____ _____
+//  __|  |   __|     |   | |  JSON for Modern C++ (supporting code)
+// |  |  |__   |  |  | | | |  version 3.12.0
+// |_____|_____|_____|_|___|  https://github.com/nlohmann/json
+//
+// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
+// SPDX-License-Identifier: MIT
+
+#include "doctest_compatibility.h"
+
+#include <nlohmann/json.hpp>
+using nlohmann::json;
+
+#include <list>
+
+namespace
+{
+TEST_CASE("Use arbitrary stdlib container")
+{
+    std::string raw_data = "[1,2,3,4]";
+    std::list<char> data(raw_data.begin(), raw_data.end());
+
+    json as_json = json::parse(data.begin(), data.end());
+    CHECK(as_json.at(0) == 1);
+    CHECK(as_json.at(1) == 2);
+    CHECK(as_json.at(2) == 3);
+    CHECK(as_json.at(3) == 4);
+}
+
+struct MyContainer
+{
+    const char* data;
+};
+
+const char* begin(const MyContainer& c)
+{
+    return c.data;
+}
+
+const char* end(const MyContainer& c)
+{
+    return c.data + strlen(c.data); // NOLINT(cppcoreguidelines-pro-bounds-pointer-arithmetic)
+}
+
+TEST_CASE("Custom container non-member begin/end")
+{
+
+    const MyContainer data{"[1,2,3,4]"};
+    json as_json = json::parse(data);
+    CHECK(as_json.at(0) == 1);
+    CHECK(as_json.at(1) == 2);
+    CHECK(as_json.at(2) == 3);
+    CHECK(as_json.at(3) == 4);
+
+}
+
+TEST_CASE("Custom container member begin/end")
+{
+    struct MyContainer2
+    {
+        const char* data;
+
+        const char* begin() const noexcept
+        {
+            return data;
+        }
+
+        const char* end() const noexcept
+        {
+            return data + strlen(data); // NOLINT(cppcoreguidelines-pro-bounds-pointer-arithmetic)
+        }
+    };
+
+    const MyContainer2 data{"[1,2,3,4]"};
+    json as_json = json::parse(data);
+    CHECK(as_json.at(0) == 1);
+    CHECK(as_json.at(1) == 2);
+    CHECK(as_json.at(2) == 3);
+    CHECK(as_json.at(3) == 4);
+}
+
+TEST_CASE("Custom iterator")
+{
+    const char* raw_data = "[1,2,3,4]";
+
+    struct MyIterator
+    {
+        using difference_type = std::size_t;
+        using value_type = char;
+        using pointer = const char*;
+        using reference = const char&;
+        using iterator_category = std::input_iterator_tag;
+
+        MyIterator& operator++()
+        {
+            ++ptr; // NOLINT(cppcoreguidelines-pro-bounds-pointer-arithmetic)
+            return *this;
+        }
+
+        reference operator*() const
+        {
+            return *ptr;
+        }
+
+        bool operator!=(const MyIterator& rhs) const
+        {
+            return ptr != rhs.ptr;
+        }
+
+        const char* ptr;
+    };
+
+    // avoid -Wunused-local-typedefs
+    CHECK(std::is_same<MyIterator::difference_type, std::size_t>::value);
+    CHECK(std::is_same<MyIterator::value_type, char>::value);
+    CHECK(std::is_same<MyIterator::pointer, const char*>::value);
+    CHECK(std::is_same<MyIterator::reference, const char&>::value);
+    CHECK(std::is_same<MyIterator::iterator_category, std::input_iterator_tag>::value);
+
+    const MyIterator begin{raw_data};
+    const MyIterator end{raw_data + strlen(raw_data)}; // NOLINT(cppcoreguidelines-pro-bounds-pointer-arithmetic)
+
+    json as_json = json::parse(begin, end);
+    CHECK(as_json.at(0) == 1);
+    CHECK(as_json.at(1) == 2);
+    CHECK(as_json.at(2) == 3);
+    CHECK(as_json.at(3) == 4);
+}
+
+} // namespace