diff --git a/test/src/unit-alt-string.cpp b/test/src/unit-alt-string.cpp
index cc05039c2..c5e891110 100644
--- a/test/src/unit-alt-string.cpp
+++ b/test/src/unit-alt-string.cpp
@@ -33,6 +33,12 @@ SOFTWARE.
 #include <string>
 #include <utility>
 
+
+/* forward declarations */
+class alt_string;
+bool operator<(const char* op1, const alt_string& op2);
+
+
 /*
  * This is virtually a string class.
  * It covers std::string under the hood.
@@ -60,17 +66,26 @@ class alt_string
     }
 
     template <typename op_type>
-    bool operator==(op_type&& op) const
+    bool operator==(const op_type& op) const
     {
         return str_impl == op;
     }
 
+    bool operator==(const alt_string& op) const
+    {
+        return str_impl == op.str_impl;
+    }
+
     template <typename op_type>
-    bool operator!=(op_type&& op) const
+    bool operator!=(const op_type& op) const
     {
         return str_impl != op;
     }
 
+    bool operator!=(const alt_string& op) const {
+        return str_impl != op.str_impl;
+    }
+
     std::size_t size() const noexcept
     {
         return str_impl.size();
@@ -87,7 +102,7 @@ class alt_string
     }
 
     template <typename op_type>
-    bool operator<(op_type&& op) const
+    bool operator<(const op_type& op) const
     {
         return str_impl < op;
     }
@@ -134,6 +149,8 @@ class alt_string
 
   private:
     std::string str_impl;
+
+    friend bool ::operator<(const char*, const alt_string&);
 };
 
 
@@ -149,6 +166,11 @@ using alt_json = nlohmann::basic_json <
                  nlohmann::adl_serializer >;
 
 
+bool operator<(const char* op1, const alt_string& op2) {
+    return op1 < op2.str_impl;
+}
+
+
 
 TEST_CASE("alternative string type")
 {
@@ -210,4 +232,34 @@ TEST_CASE("alternative string type")
         alt_string dump = doc.dump();
         CHECK(dump == R"({"foo":"bar"})");
     }
+
+    SECTION("equality")
+    {
+        alt_json doc;
+        doc["Who are you?"] = "I'm Batman";
+
+        CHECK("I'm Batman" == doc["Who are you?"]);
+        CHECK(doc["Who are you?"]  == "I'm Batman");
+        CHECK_FALSE("I'm Batman" != doc["Who are you?"]);
+        CHECK_FALSE(doc["Who are you?"]  != "I'm Batman");
+
+        CHECK("I'm Bruce Wayne" != doc["Who are you?"]);
+        CHECK(doc["Who are you?"]  != "I'm Bruce Wayne");
+        CHECK_FALSE("I'm Bruce Wayne" == doc["Who are you?"]);
+        CHECK_FALSE(doc["Who are you?"]  == "I'm Bruce Wayne");
+
+        {
+            const alt_json& const_doc = doc;
+
+            CHECK("I'm Batman" == const_doc["Who are you?"]);
+            CHECK(const_doc["Who are you?"] == "I'm Batman");
+            CHECK_FALSE("I'm Batman" != const_doc["Who are you?"]);
+            CHECK_FALSE(const_doc["Who are you?"] != "I'm Batman");
+
+            CHECK("I'm Bruce Wayne" != const_doc["Who are you?"]);
+            CHECK(const_doc["Who are you?"] != "I'm Bruce Wayne");
+            CHECK_FALSE("I'm Bruce Wayne" == const_doc["Who are you?"]);
+            CHECK_FALSE(const_doc["Who are you?"] == "I'm Bruce Wayne");
+        }
+    }
 }