test treewide: iwyu

These changes are done by running iwyu manually under clang14.

Suppressed some obvious impl or details headers. Kept the recommended
public headers.

IWYU can increase readability, make maintenance easier, and avoid errors
in some cases. See details in
https://github.com/include-what-you-use/include-what-you-use/blob/master/docs/WhyIWYU.md.

This commit also uses its best effort to correct obvious errors through
iwyu pragma.
See reference here:
https://github.com/include-what-you-use/include-what-you-use#how-to-correct-iwyu-mistakes

Tested: unit test passed.

Signed-off-by: Nan Zhou <nanzhoumails@gmail.com>
Change-Id: I983b6f75601707cbb0f2f04546c3362ff4ba7fee
diff --git a/include/ut/openbmc_dbus_rest_test.cpp b/include/ut/openbmc_dbus_rest_test.cpp
index 7efd10d..b01e92a 100644
--- a/include/ut/openbmc_dbus_rest_test.cpp
+++ b/include/ut/openbmc_dbus_rest_test.cpp
@@ -1,7 +1,12 @@
 #include "openbmc_dbus_rest.hpp"
 
-#include <gmock/gmock.h>
-#include <gtest/gtest.h>
+#include <gmock/gmock.h> // IWYU pragma: keep
+#include <gtest/gtest.h> // IWYU pragma: keep
+
+// IWYU pragma: no_include <gtest/gtest-message.h>
+// IWYU pragma: no_include <gtest/gtest-test-part.h>
+// IWYU pragma: no_include "gtest/gtest_pred_impl.h"
+// IWYU pragma: no_include <gmock/gmock-matchers.h>
 
 namespace crow::openbmc_mapper
 {