It doesn't look like one needs all of MLJ for testing. I think MLJBase should suffice.
If you are using any measures (metrics) from MLJ, then now that this has just merged, you will additionally need to add StatisticalMeasures.jl as a test dependency and add using StatisticalMeasures to your tests.
https://github.com/antoninkriz/TimeSeriesClassification.jl/blob/bbf35d1722c0de9907aba6ee2bf57cf7bfd197fd/test/MiniRocket/tests.jl#L4
It doesn't look like one needs all of MLJ for testing. I think MLJBase should suffice.
If you are using any measures (metrics) from MLJ, then now that this has just merged, you will additionally need to add StatisticalMeasures.jl as a test dependency and add
using StatisticalMeasures
to your tests.