Fix all Doxygen errors and make any future errors fatal (#118) ...

* Start working on fixing doxygen warnings

* Upgrade doxyfile to Doxygen 1.9.1

* Clean up some unmatched groups and add some exclusions

* Fix docs for rtos::ThisThread not showing up

* Fix up KV store docs

* Fix incorrect @files, some more incorrect groups

* Fix lots of broken links

* Start fixing mbedtls groups

* Fix more mbedtls docs

* Fix remaining mbedtls files with missing or incorrect grouping

* Fix a huge amount of PSA docs errors

* Fix a few more mbedtls docs errors

* Fix __cplusplus not defined for docs, clean up call in callback typedef, fix some docs errors

* Fix some broken doc links in HAL headers

* Fix more PSA doc errors

* Fix some doxygen errors in networking code

* Fix lots of network related doc errors

* Try and fix some CI failures

* Use Doxygen Action instead of doxygen in Mbed container to get the right version

* Try removing docs check

* Add first part of doxygen action

* Add next part of doxygen action

* Fix yaml syntax error

* Add in license check fix

* Try using verbose scancode

* Fix some more docs issues, workaround scancode-toolkit#3179

* Clean up the LoRaRadio get_state() function on each implementation.  Also fix some other compile and doc errors.

* Fix all remaining doxygen errors

* Fix escaping, for realsies this time

* Remove Doxygen unsupported config options, fix some more get_status() declarations

* Fix some UNITTESTS build errors

* Fix one more compile error

* Another unittest error

Unit tests: Remove redundant CMake target mbed-headers-base ...

Individual libraries' `target_h` stub headers have now all been moved
from `mbed-headers-base` to `mbed-headers-<library>`.

Note: Even though headers previously in `target_h` are technically
stubs/fakes too, they are used by not only unit tests but also regular
libraries when compiled for unit tests, because no target-specific HAL
implementation exists in this case. In order for regular library
sources to pick up `target_h` headers, those headers must

* have the same names as regular headers
* appear first in include paths

This is why those headers are part of `mbed-headers-<library>` and not
`mbed-stubs-<library>`. Before this refactoring, `mbed-headers-base`
was the first in unit tests' include paths.

unittests: Test_LoRaWANStack.acquire_rx_metadata: Fix SEGFAULT ...

We failed to set `LoRaMac_stub::mlme_ind_ptr` to a valid pointer. When
we tried to dereference it in `LoRaWANStack::process_reception` we hit a
SEGFAULT.

unittests: Fix Test_LoRaWANStack.acquire_tx_metadata ...

This test was relying on the state of `LoRaMac_stub::bool_true_counter`
to be set to 1 from a previous test. When the test was ran in isolation
the `LoRaWANStack::rx_timeout_interrupt_handler` callback would fail
because we weren't returning true from the stub implementation of
`LoRaMac::nwk_joined`. Due to this
`LoRaWANStack::post_process_tx_no_reception` was never called. This
caused the LoRaWANStack object to think the "tx_metadata" was "stale"
(i.e the data hadn't changed since any previous read). So, when we
attempted to call `LoRaWANStack::acquire_tx_metadata` it returned
`LORAWAN_STATUS_METADATA_NOT_AVAILABLE` as it thought we had no new
metadata to report, causing the test assertion to fail.

unittests: Test_LoRaMac.post_process_mcps_req: Fix segfault ...

We had commented out a line where we reset LoRaPHY_stub::uint16_value to
0. This was causing an invalid array access in
LoRaMac::handle_data_frame, when trying to extract the
_mps_indication.channel from list of channel_params_t returned by
lora_phy->get_phy_channels.

CMake: unittests: Show all tests in CTest report ...

Previously a test executable was recognised as a single test by CTest.
However, test executables usually contain multiple test cases, the
results of the test cases should be individually reported. With our
previous setup we could miss test case failures that didn't cause the
executable to return an error code.

This commit uses gtest_discover_test to discover all test cases in a
test executable. This enables CTest to match test passes and failures
from the googletest binary output.

CMake: unittests: Remove trailing whitespace

test: lorawanstack: Use valid message type ...

We previously made up an invalid message type, which was roughly
`MCPS_MULTICAST | 0x40`. This causes an MBED_ASSERT failure in the
handle_rx function, as it uses an assert to validate the message type
passed to it (in convert_to_msg_flag()). Use the valid message type
MCPS_MULTICAST instead in the handle_rx unit test.

unittests: Test_LoRaWANTimer.start: Fix test failure ...

We weren't initialising the mocks correctly, so an MBED_ASSERT failed in
`LoRaWANTimer::start` because the "timer_id" was not set.

cmake: Remove trailing whitespace ...

Remove trailing whitespace from lorawantimer's CMakeLists.txt.

Remove mbed-headers-connectivity ...

Moved all the headers out of mbed-headers-connectivity, and these changes remove
that headers lib reference from lorawan and cellular unit tests

Unit tests: Make lorawan test header dependencies explicit ...

To quote @LDong-Arm - "The CMake target `mbed-headers` brings in all
headers, and we are gradually moving away from it and explicitly use
only headers needed by each unit test."

CMake: Update netsocket, lorawan unittest to use mbed-stubs-mbedtls ...

Update netsocket and lorawan unit tests to link with a mbed-stubs-mbedtls
library that it depends on instead of link with mbed-stubs
which is a group of stubs libraries.

CMake: Move mbedtls stubs to the mbedtls dir ...

Move the connectivity mbedtls stubs into the connectivity/mbedtls
component directory. So we can avoid duplicating the mbed-os source
tree in a central UNITTESTS folder.

CMake: Move lorawan stub headers to the lorawan/tests/UNITTESTS/double dir ...

Previously all the lorawan stubs headers under mbed-stubs-headers,
so this PR move all lorawan stubs headers under
cellular/tests/UNITTESTS/double directory and update CMake to include
stubs headers into mbed-stubs-lorawan library to make lorawan stubs to be self-contained

CMake: unit-tests: Make lorawan stub only depend on headers it uses ...

Previously the connectivity lorawan stub library depended on
`mbed-headers`, which is a collection of all available headers
in mbed-os. To make it easier to separate the library, only depend
on the headers we're using.

CMake: Update lorawan unittest to use mbed-headers-lorawan lib ...

Update lorawan unit test to link only with a mbed-headers-lorawan
library that it depends on instead of link with mbed-headers
which is a group of headers libraries.

CMake: unit-tests: Add mbed-headers-lorawan headers library ...

Previously, all lorawan headers made as a part of the
mbed-headers-connectivity library. To make it easier to separate all
the lorawan headers into the separate mbed-headers-lorawan library
and keep them, as part of lorawan stubs CMake. This makes the lorawan
stubs more self-contained and improves the composition of the library.

CMake: Update lorawan unittest to use mbed-stubs-lorawan ...

Update lorawan unit test to link only with a mbed-stubs-lorawan
library that it depends on instead of link with mbed-stubs
which is a group of stubs libraries.

CMake: Move lorawan stubs to the lorawan dir ...

Move the connectivity lorawan stubs into the connectivity/lorawan
component directory. So we can avoid duplicating the mbed-os source
tree in a central UNITTESTS folder.

CMake: unit-tests: Add mbed-headers-cellular headers library ...

- Previously all cellular header made as a part of the
mbed-headers-connectivity library. To make it easier to separate all
the cellular headers into the separate mbed-headers-cellular library
and keep them as part of cellular stub CMake. This makes the cellular
stubs more self-contained and improves the composition of the library.
- Update all unit test that depends on cellular headers with mbed-headers-cellular library

CMake: Require TEST_SOURCES in greentea CMake file ...

Assumption that greentea test file is always named main.cpp is
incorrect. Updated mbed_greentea_add_test() macro to make TEST_SOURCES
parameter compulsory, which is used to specify greentea test
file(s). This allows tests to use C, or have a different name.
Therefore also updated all pre-existing greentea test CMake files to
explicity add main.cpp to TEST_SOURCES.

Early test skip ...

Adding mbed-os subdirectories that are not required for a specific project to .mbedignore is a good way to reduce compilation time. Sometimes it happens that tests depend on ignored files, which causes the test-build to fail even though the corresponding feature/component
is not configured. The reason is that the conditional that skips the test is placed after the includes.

Merge pull request #14708 from Patater/fix-test-function-return ...

test: Fix function does not return a value warnings

test: Fix function does not return a value warnings ...

Many test stub functions are meant to return a value, but weren't. Clang
would generate a warning for each instance where we weren't returning
anything in a function that was meant to return a value.

    warning: non-void function does not return a value [-Wreturn-type]

For a specific example, my_radio::time_on_air() is supposed to return a
uint32_t, but wasn't returning anything. We'll return a zero instead of
relying on undefined behavior.

Without this, clang 11.0.1 was generating a virtual function
implementation with a `ud2` instruction to abort at run-time, causing
some execution of some unit tests to abort.

    Running main() from gmock_main.cc
    [==========] Running 10 tests from 1 test suite.
    [----------] Global test environment set-up.
    [----------] 10 tests from Test_LoRaPHYUS915
    [ RUN      ] Test_LoRaPHYUS915.constructor
    [       OK ] Test_LoRaPHYUS915.constructor (0 ms)
    [ RUN      ] Test_LoRaPHYUS915.restore_default_channels
    [       OK ] Test_LoRaPHYUS915.restore_default_channels (0 ms)
    [ RUN      ] Test_LoRaPHYUS915.rx_config
    [       OK ] Test_LoRaPHYUS915.rx_config (0 ms)
    [ RUN      ] Test_LoRaPHYUS915.tx_config
    Process 35669 stopped
    * thread #1, name = 'lorawan-loraphy-', stop reason = signal SIGILL: privileged instruction
        frame #0: 0x0000000000276f73 lorawan-loraphy-us915-unittest`my_radio::time_on_air(this=0x0000000800c2b048, modem=MODEM_LORA, pkt_len='\0') at Test_LoRaPHYUS915.cpp:90:5
       87       };
       88
       89       virtual uint32_t time_on_air(radio_modems_t modem, uint8_t pkt_len)
    -> 90       {
       91       };
       92
       93       virtual bool perform_carrier_sense(radio_modems_t modem,
    (lldb) disassemble --pc
    lorawan-loraphy-us915-unittest`my_radio::time_on_air:
    ->  0x276f73 <+67>: ud2
        0x276f75:       int3
        0x276f76:       int3
        0x276f77:       int3
    (lldb)

CMake: Remove all unittest.cmake script from test suite ...

- Remove redundant cmake script as already added the CMake configuration file
- Remove redundant empty_baseline as it is no longer needed with the help of CMake configuration file

CMake: Refactor lorawan unittest cmake ...

- Add CMakeLists.txt file to all lorawan test suite

STM32WL LORA : enable connectivity test

Merge pull request #14228 from ARMmbed/rename_greentea_test_macro ...

CMake: rename greentea test macro

CMake: rename greentea test macro