Merge branch '71-tests-for-conversion-db' into develop

src/tests/test_io/test_data_container/data/test.csv

src/tests/test_io/test_data_container/data/test.json

src/tests/test_io/test_data_container/test_data_container.py

src/tests/test_plots/test_frequency_domain/data/flipper1.TXT

src/tests/test_plots/test_frequency_domain/data/flipper2.TXT

src/tests/test_plots/test_frequency_domain/data/flipper3.TXT

src/tests/test_plots/test_frequency_domain/data/scope_0.csv

.../test_plots/test_frequency_domain/test_amplitude_phase.py

..._plots/test_frequency_domain/test_relative_input_noise.py

src/tests/test_plots/test_time_domain/data/20180606_001.csv

src/tests/test_plots/test_time_domain/test_time_domain.py