expand tests

src/test_lib_json/main.cpp

diff --git a/src/test_lib_json/main.cpp b/src/test_lib_json/main.cpp
index ca49ed5..7ebd466 100644
--- a/src/test_lib_json/main.cpp
+++ b/src/test_lib_json/main.cpp
@@ -150,6 +150,8 @@
   /// Normalize the representation of floating-point number by stripped leading
   /// 0 in exponent.
   static Json::String normalizeFloatingPointStr(const Json::String& s);
+
+  void runCZStringTests();
 };
 
 Json::String ValueTest::normalizeFloatingPointStr(const Json::String& s) {
@@ -167,6 +169,44 @@
   return normalized + exponent;
 }
 
+void ValueTest::runCZStringTests() {
+  // 1. Copy Constructor (Index)
+  Json::Value::CZString idx1(123);
+  Json::Value::CZString idx2(idx1);
+  JSONTEST_ASSERT_EQUAL(idx2.index(), 123);
+
+  // 2. Move Constructor (Index)
+  Json::Value::CZString idx3(std::move(idx1));
+  JSONTEST_ASSERT_EQUAL(idx3.index(), 123);
+
+  // 3. Move Assignment (Index)
+  Json::Value::CZString idx4(456);
+  idx4 = std::move(idx3);
+  JSONTEST_ASSERT_EQUAL(idx4.index(), 123);
+
+  // 4. Copy Constructor (String)
+  Json::Value::CZString str1("param", 5,
+                             Json::Value::CZString::duplicateOnCopy);
+  Json::Value::CZString str2((str1)); // copy makes it duplicate (owning)
+  JSONTEST_ASSERT_STRING_EQUAL(str2.data(), "param");
+
+  // 5. Move Constructor (String)
+  // Move from Owning string (str2)
+  Json::Value::CZString str3(std::move(str2));
+  JSONTEST_ASSERT_STRING_EQUAL(str3.data(), "param");
+
+  // 6. Move Assignment (String)
+  Json::Value::CZString str4("other", 5,
+                             Json::Value::CZString::duplicateOnCopy);
+  Json::Value::CZString str5((str4)); // owning "other"
+  // Move-assign owning "param" (str3) into owning "other" (str5)
+  // This verifies we don't leak "other" (if fixed) and correctly take "param"
+  str5 = std::move(str3);
+  JSONTEST_ASSERT_STRING_EQUAL(str5.data(), "param");
+}
+
+JSONTEST_FIXTURE_LOCAL(ValueTest, CZStringCoverage) { runCZStringTests(); }
+
 JSONTEST_FIXTURE_LOCAL(ValueTest, checkNormalizeFloatingPointStr) {
   struct TestData {
     std::string in;