feat: add config verify flag (#1814)

fixes #1806

tests/unit/app/VerifyConfigTests.cpp

@@ -0,0 +1,62 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of clio: https://github.com/XRPLF/clio
+    Copyright (c) 2025, the clio developers.
+
+    Permission to use, copy, modify, and distribute this software for any
+    purpose with or without fee is hereby granted, provided that the above
+    copyright notice and this permission notice appear in all copies.
+
+    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
+    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+    ANY  SPECIAL,  DIRECT,  INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
+    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+//==============================================================================
+
+#include "app/VerifyConfig.hpp"
+#include "util/TmpFile.hpp"
+#include "util/newconfig/FakeConfigData.hpp"
+
+#include <gtest/gtest.h>
+
+using namespace app;
+using namespace util::config;
+
+TEST(VerifyConfigTest, InvalidConfig)
+{
+    auto const tmpConfigFile = TmpFile(kJSON_DATA);
+
+    // false because json data(kJSON_DATA) is not compatible with current configDefintion
+    EXPECT_FALSE(verifyConfig(tmpConfigFile.path));
+}
+
+TEST(VerifyConfigTest, ValidConfig)
+{
+    auto const tmpConfigFile = TmpFile(kVALID_JSON_DATA);
+
+    // current example config should always be compatible with configDefinition
+    EXPECT_TRUE(verifyConfig(tmpConfigFile.path));
+}
+
+TEST(VerifyConfigTest, ConfigFileNotExist)
+{
+    EXPECT_FALSE(verifyConfig("doesn't exist Config File"));
+}
+
+TEST(VerifyConfigTest, InvalidJsonFile)
+{
+    // invalid json because extra "," after 51233
+    static constexpr auto kINVALID_JSON = R"({
+                                             "server": {
+                                                "ip": "0.0.0.0",
+                                                "port": 51233, 
+                                            }
+                                        })";
+    auto const tmpConfigFile = TmpFile(kINVALID_JSON);
+
+    EXPECT_FALSE(verifyConfig(tmpConfigFile.path));
+}