Flesh out the repository with example and tests

tests/CMakeLists.txt

@@ -0,0 +1,34 @@
+include(FetchContent)
+
+FetchContent_Declare(
+    Unity
+        GIT_REPOSITORY https://github.com/ThrowTheSwitch/Unity.git
+        GIT_TAG v2.6.1
+)
+FetchContent_MakeAvailable(Unity)
+
+add_executable(
+    json_test
+    json_test.c
+)
+set_target_properties(
+    json_test
+    PROPERTIES
+        C_STANDARD 23
+        C_STANDARD_REQUIRED ON
+        C_EXTENSIONS OFF
+)
+target_link_libraries(
+    json_test
+    PRIVATE
+        json
+        unity::framework
+)
+target_include_directories(
+    json_test
+    PRIVATE
+        ${CMAKE_SOURCE_DIR}
+)
+
+add_test(NAME json_test COMMAND json_test)
+

tests/json_test.c

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+#include <stdio.h>
+#include <string.h>
+
+#include <unity.h>
+
+#include <json.h>
+
+static FILE* tmp = nullptr;
+static char buffer[256];
+
+static Json json;
+
+void setUp()
+{
+    tmp = tmpfile();
+    TEST_ASSERT_NOT_NULL(tmp);
+
+    json = json_init(tmp, MINIFIED);
+}
+
+void tearDown()
+{
+    json_free(&json);
+
+    if (tmp) {
+        fclose(tmp);
+        tmp = nullptr;
+    }
+}
+
+void test_json_add_string()
+{
+    json_add_string(&json, "string");
+    fflush(tmp);
+    rewind(tmp);
+
+    char buffer[256];
+    auto n = fread(buffer, 1, sizeof(buffer) - 1, tmp);
+    buffer[n] = '\0';
+
+    TEST_ASSERT_EQUAL_STRING("\"string\"", buffer);
+}
+
+int main()
+{
+    UNITY_BEGIN();
+    {
+        RUN_TEST(test_json_add_string);
+    }
+    return UNITY_END();
+}
+