Truffle and solidity tips and tricks - test events in unit tests

If you use truffle and want to test solidity with javascript unit test, you might want to test the raised events as well. As result gives back the whole transaction including the event log, the easiest way to get the event is to get them directly from the event log:

   return ContractInstance.functionCall({from: accounts[0]});       

   }).then(function(result) {

- result contains the whole transactions

- result.logs contains the whole log

- result.logs[0].event contains the first event

So, an assert that checks if an event was raised might simply look like:

assert.equal(result.logs[0].event, "EventName", "Event raised");