diff --git a/test/src/unit-fancy-serialization.cpp b/test/src/unit-fancy-serialization.cpp
new file mode 100644
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+++ b/test/src/unit-fancy-serialization.cpp
@@ -0,0 +1,97 @@
+/*
+    __ _____ _____ _____
+ __|  |   __|     |   | |  JSON for Modern C++ (test suite)
+|  |  |__   |  |  | | | |  version 3.1.2
+|_____|_____|_____|_|___|  https://github.com/nlohmann/json
+
+Licensed under the MIT License <http://opensource.org/licenses/MIT>.
+SPDX-License-Identifier: MIT
+Copyright (c) 2013-2018 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 "catch.hpp"
+
+#include <nlohmann/json.hpp>
+using nlohmann::json;
+
+TEST_CASE("serialization")
+{
+    SECTION("operator<<")
+    {
+        SECTION("no given width")
+        {
+            std::stringstream ss;
+            json j = {"foo", 1, 2, 3, false, {{"one", 1}}};
+            ss << j;
+            CHECK(ss.str() == "[\"foo\",1,2,3,false,{\"one\":1}]");
+        }
+
+        SECTION("given width")
+        {
+            std::stringstream ss;
+            json j = {"foo", 1, 2, 3, false, {{"one", 1}}};
+            ss << std::setw(4) << j;
+            CHECK(ss.str() ==
+                  "[\n    \"foo\",\n    1,\n    2,\n    3,\n    false,\n    {\n        \"one\": 1\n    }\n]");
+        }
+
+        SECTION("given fill")
+        {
+            std::stringstream ss;
+            json j = {"foo", 1, 2, 3, false, {{"one", 1}}};
+            ss << std::setw(1) << std::setfill('\t') << j;
+            CHECK(ss.str() ==
+                  "[\n\t\"foo\",\n\t1,\n\t2,\n\t3,\n\tfalse,\n\t{\n\t\t\"one\": 1\n\t}\n]");
+        }
+    }
+
+    SECTION("operator>>")
+    {
+        SECTION("no given width")
+        {
+            std::stringstream ss;
+            json j = {"foo", 1, 2, 3, false, {{"one", 1}}};
+            j >> ss;
+            CHECK(ss.str() == "[\"foo\",1,2,3,false,{\"one\":1}]");
+        }
+
+        SECTION("given width")
+        {
+            std::stringstream ss;
+            json j = {"foo", 1, 2, 3, false, {{"one", 1}}};
+            ss.width(4);
+            j >> ss;
+            CHECK(ss.str() ==
+                  "[\n    \"foo\",\n    1,\n    2,\n    3,\n    false,\n    {\n        \"one\": 1\n    }\n]");
+        }
+
+        SECTION("given fill")
+        {
+            std::stringstream ss;
+            json j = {"foo", 1, 2, 3, false, {{"one", 1}}};
+            ss.width(1);
+            ss.fill('\t');
+            j >> ss;
+            CHECK(ss.str() ==
+                  "[\n\t\"foo\",\n\t1,\n\t2,\n\t3,\n\tfalse,\n\t{\n\t\t\"one\": 1\n\t}\n]");
+        }
+    }
+}