Clear key after matching on it

tests/test_commit_request.cpp

@@ -195,8 +195,8 @@ TEST_CASE("CommitRequest precondition and operation validation") {
                 {
                     "type": "range_read",
                     "version": 12340,
-                    "begin": "",
-                    "end": ""
+                    "begin": "dGVzdA==",
+                    "end": "dGVzdFo="
                 }
             ]
         })";
@@ -206,6 +206,9 @@ TEST_CASE("CommitRequest precondition and operation validation") {
     INFO("Parse result: " << parse_result);
     INFO("Parse complete: " << request.is_parse_complete());
     INFO("Parse error: " << request.has_parse_error());
+    const char *error_msg = request.get_parse_error();
+    INFO("Parse error message: " << (error_msg ? std::string(error_msg)
+                                               : "none"));
     INFO("Leader ID: '" << request.leader_id() << "'");
     INFO("Read version: " << request.read_version());