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)
Jaeden Amero
Rajkumar Kanagaraj