Use gtest's asserts instead of std::assert in simple switch grpc gtests.

[fruffy]

Originally posted by @fruffy in #1373

[vanshikaaa2006]

Hi, I am learning C++ and open-source contributions. I would like to work on this issue and replace the std::assert statements with gtest assertions. Please let me know if I can take this task.

[fruffy]

Yes, sure!

[sanket-jadhav-cse]

Hi @fruffy, I noticed this issue was claimed a while ago but I couldn't find an associated PR. Is it still being worked on? If not, I'd be happy to take it.

[sanket-jadhav-cse]

@fruffy I investigated this while working on #1436 and ran into a design question.

Replacing std::assert with ASSERT_* works only in void test contexts. In this codebase, several assertions are inside non-void functions (for example test() in example.cpp and parse_p4info() in utils.cpp), so replacing them with ASSERT_* causes compilation failures.

I also noticed that example.cpp is built as a standalone executable rather than a GoogleTest test.

Should this issue be interpreted as:

• replacing asserts only where GoogleTest assertions are applicable,
• refactoring example.cpp into a proper GoogleTest test,
• or something else?

I'd appreciate your guidance before I continue with the implementation.

[fruffy]

Yes, let's investigate why it could be a standalone executable and what for. If there is no good reason, we should choose the second option and clean this up. If there is a good reason, we should get rid of the asserts and just return error codes.

[sanket-jadhav-cse]

@fruffy I finished the investigation.

From the repository history, example.cpp was intentionally kept as a standalone example when the original tests were moved to GoogleTest (commit 19354d5). It is still executed through example.run, which relies on the executable's exit status.

Based on that, I think the standalone executable has a valid purpose, so following your suggestion I will replace the assert() calls with explicit error handling and return error codes instead of converting it into a GoogleTest.