truffle-assertions

truffle-assertions

This package adds additional assertions that can be used to test Ethereum smart contracts inside Truffle tests.

Installation

truffle-assertions can be installed through npm:

npm install truffle-assertions

Usage

To use this package, import it at the top of the Truffle test file:

const truffleAssert = require('truffle-assertions');

Assertions

truffleAssert.eventEmitted(result, eventType, filter)

The eventEmitted assertion checks that an event with type eventType has been emitted by the transaction with result result. A filter function can be passed along to further specify requirements for the event arguments:

truffleAssert.eventEmitted(result, 'TestEvent', (ev) => {
    return ev.param1 === 10 && ev.param2 === ev.param3;
});

When the filter parameter is set to null, the assertion checks just for event type:

truffleAssert.eventEmitted(result, 'TestEvent', null);

truffleAssert.eventNotEmitted(result, eventType, filter)

The eventNotEmitted assertion checks that an event with type eventType has not been emitted by the transaction with result result. A filter function can be passed along to further specify requirements for the event arguments:

truffleAssert.eventNotEmitted(result, 'TestEvent', (ev) => {
    return ev.param1 === 10 && ev.param2 === ev.param3;
});

When the filter parameter is set to null, the assertion checks just for event type:

truffleAssert.eventNotEmitted(result, 'TestEvent', null);