is there a way to test yeast before committing a whole batch of flour to it?

There is, it takes five minutes, and it should be a permanent habit for any yeast packet you don't fully trust.

The proof test: warm water (comfortably warm to a finger, not hot - hot water is how healthy yeast gets murdered and blamed for it), a pinch of sugar, stir in a spoon of the yeast. Wait 5-10 minutes. Living yeast foams up into a beige, beer-smelling froth. Dead yeast just sits there as sad sediment.

Foam = proceed with the batch. Flat = you just saved 500g of flour and an evening.

Storage is the usual killer btw, not the factory - India's heat and humidity age yeast fast. Keep opened yeast airtight in the FRIDGE, buy smaller packets more often, and date the packet when you open it. Instant yeast well-stored lasts months... badly stored, weeks. The five-minute test is your insurance either way.