add unit test: checking dump to alternative string type

test/src/unit-alt-string.cpp

@@ -0,0 +1,165 @@
+/*
+    __ _____ _____ _____
+ __|  |   __|     |   | |  JSON for Modern C++ (test suite)
+|  |  |__   |  |  | | | |  version 3.1.1
+|_____|_____|_____|_|___|  https://github.com/nlohmann/json
+
+Licensed under the MIT License <http://opensource.org/licenses/MIT>.
+Copyright (c) 2018 Vitaliy Manushkin <agri@akamo.info>.
+
+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 "catch.hpp"
+
+#include <nlohmann/json.hpp>
+#include <string>
+#include <utility>
+
+/*
+ * This is virtually a string class.
+ * It covers std::string under the hood.
+ */
+class alt_string
+{
+  public:
+    using value_type = std::string::value_type;
+
+    alt_string(const char* str): str_impl(str) {}
+    alt_string(const char* str, size_t count): str_impl(str, count) {}
+    alt_string(size_t count, char chr): str_impl(count, chr) {}
+    alt_string() = default;
+
+    template <typename...TParams>
+    alt_string& append(TParams&& ...params)
+    {
+        str_impl.append(std::forward<TParams>(params)...);
+        return *this;
+    }
+
+    void push_back(char c)
+    {
+        str_impl.push_back(c);
+    }
+
+    template <typename op_type>
+    bool operator==(op_type&& op) const
+    {
+        return str_impl == op;
+    }
+
+    template <typename op_type>
+    bool operator!=(op_type&& op) const
+    {
+        return str_impl != op;
+    }
+
+    size_t size() const noexcept
+    {
+        return str_impl.size();
+    }
+
+    void resize (size_t n)
+    {
+        str_impl.resize(n);
+    }
+
+    void resize (size_t n, char c)
+    {
+        str_impl.resize(n, c);
+    }
+
+    template <typename op_type>
+    bool operator<(op_type&& op) const
+    {
+        return str_impl < op;
+    }
+
+    bool operator<(const alt_string& op) const
+    {
+        return str_impl < op.str_impl;
+    }
+
+    const char* c_str() const
+    {
+        return str_impl.c_str();
+    }
+
+    char& operator[](int index)
+    {
+        return str_impl[index];
+    }
+
+    const char& operator[](int index) const
+    {
+        return str_impl[index];
+    }
+
+    char& back()
+    {
+        return str_impl.back();
+    }
+
+    const char& back() const
+    {
+        return str_impl.back();
+    }
+
+  private:
+    std::string str_impl;
+};
+
+
+using alt_json = nlohmann::basic_json <
+                 std::map,
+                 std::vector,
+                 alt_string,
+                 bool,
+                 std::int64_t,
+                 std::uint64_t,
+                 double,
+                 std::allocator,
+                 nlohmann::adl_serializer >;
+
+
+
+TEST_CASE("alternative string type")
+{
+    SECTION("dump")
+    {
+        alt_json doc;
+        doc["pi"] = 3.141;
+        doc["happy"] = true;
+        doc["name"] = "I'm Batman";
+        doc["nothing"] = nullptr;
+        doc["answer"]["everything"] = 42;
+        doc["list"] = { 1, 0, 2 };
+        doc["object"] = { {"currency", "USD"}, {"value", 42.99} };
+
+        alt_string dump = doc.dump();
+
+        const char* const expect_str =
+            R"({"answer":{"everything":42},)"
+            R"("happy":true,"list":[1,0,2],)"
+            R"("name":"I'm Batman","nothing":null,)"
+            R"("object":{"currency":"USD","value":42.99},)"
+            R"("pi":3.141})";
+        CHECK(dump == expect_str);
+    }
+}