Modified the tests to use mock functionality of get_child_port function under portconfig utility

[samaity]

Signed-off-by: Sangita Maity [email protected]

What I did
Modified the tests to use mock functionality of get_child_port function under portconfig utility. This will remove the dependency of port config utility in the sonic-buildimage and make the test case more robust specific to the DPB cli utility.

How I did it
used MagicMock feature

How to verify it
All test cases are passed in config_dpb_test.py file

tests/config_dpb_test.py::TestConfigDPB::test_get_breakout_options PASSED [ 10%]
tests/config_dpb_test.py::TestConfigDPB::test_config_breakout_extra_table_warning PASSED [ 11%]
tests/config_dpb_test.py::TestConfigDPB::test_config_breakout_verbose PASSED [ 11%]
tests/config_dpb_test.py::TestConfigDPB::test_config_breakout_negative_cases PASSED [ 11%]
tests/config_dpb_test.py::TestConfigDPB::test_config_breakout_various_modes PASSED [ 11%]

[samaity]

retest this please

[samaity]

@jleveque -- Kindly review whenever possible. need help in merging the code. Thanks!

[samaity]

Thanks, @jleveque !!!