Fix warnings in tcp/udp UT

[JohanBertrand]

Related Issue(s)	#2706
Has Unit Tests (y/n)
Documentation Included (y/n)

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Change Description

I am not sure we want to have those changes in the codebase. That could be used as a baseline for a better update.

Most of the warnings in the UT with TCP/UDP module should be fixed with those changes. A mutex is making sure that the receive/open/startup functions are called only if the stop/close function are not going to be called in an other thread.

I added the changes in the unit tests instead of the class itself (in open/close), because I did not find a way to make it work properly.

I also needed to make recv to stop iterating if errno == EAGAIN to avoid a timeout. I'm not sure if that's the proper way to fix this issue.

The only warning still happening for me, after 10.000 tests, is the following (happened only once):

[ RUN      ] Reconnect.ReceiveThreadReconnect
Listening for single client at 127.0.0.1:32769
Connected to 127.0.0.1:32769 as a tcp client
Accepted client at 127.0.0.1:32769
Connected to 127.0.0.1:32769 as a tcp client
Accepted client at 127.0.0.1:32769
Connected to 127.0.0.1:32769 as a tcp client
Accepted client at 127.0.0.1:32769
Accepted client at 127.0.0.1:32769
[WARNING] Failed to recv from port with status -8 and errno 0

I feel like the warnings in the test should make the UT to fail. However, I am not sure how to catch the warning streamed through Fw::Logger::logMsg.

Also fix an error in StringUtils.cpp when compiled on ubuntu20.04 with a FW_ASSERT:

/home/fprime/Fw/Types/StringUtils.cpp:51:40: error: comparison of integer expressions of different signedness: ‘FwSizeType’ {aka ‘long unsigned int’} and ‘long int’ [-Werror=sign-compare]
   51 |     FW_ASSERT((source_size - sub_size) <= std::numeric_limits<FwSignedSizeType>::max());

[LeStarch]

This makes sense!

[LeStarch]

These locks should be done in the shutdown and close methods, not just the UT.

[JohanBertrand]

I moved the mutex in the close/shutdown functions. I had to update the TcpServerTester.cpp a bit for it to work: the client needs to be closed after the server is closed. I do not have the explanation for this behavior, but otherwise I was getting the following warning:

Connected to 127.0.0.1:57755 as a tcp client
Accepted client at 127.0.0.1:57755
[WARNING] Failed to recv from port with status -8 and errno 0

There was a comment stating: // Client must be closed first or the server risks binding to an existing address. Let me know if it is a problem.

[JohanBertrand]

I also added the muted on the stop function. Can you confirm that it is something that is expected?

[JohanBertrand]

@LeStarch is there something we can do in the UT to check that no warnings are logged using Fw::Logger::logMsg, and cause the UT to fail if it contains warnings?

During my tests, I used that warning messages to realize that something was wrong.

I also used a timeout to make sure that the tests were not taking too long. It was especially useful for checking that the TcpServer tests were working properly. The test could take a few seconds on failure, where it's supposed to be less than 500ms in nominal conditions on my hardware. However, I don't think that's something that can/should be implemented, since it's hardware dependent.

[JohanBertrand]

@LeStarch Can you confirm that we do not need this shutdown, since it's already part of the stop function?

Keeping it is causing a timeout on my setup (the UT tasking more than 1s)

[JohanBertrand]

@LeStarch @thomas-bc Let me know if there is something else to change in this PR