ganache-time-traveler

A ganache utility that simplifies writing time dependent or stateless tests on a local Ethereum blockchain.

• Read my Medium Post

• Watch my Presentation

• Time Contract Example

NOTE:

• this only works with ganache-cli
• this only works locally

Tool Dependencies

• ganache-cli
• truffle

Install

• npm i ganache-time-traveler

Usage

The general outline is to add require at the top of your tests

const timeMachine = require('ganache-time-traveler');

add the beforeEach and afterEach hooks into your truffle test file

contract('Test', async (accounts) =>  {

   let exampleContract;

   beforeEach(async() => {
       let snapshot = await timeMachine.takeSnapshot();
       snapshotId = snapshot['result'];
   });

   afterEach(async() => {
       await timeMachine.revertToSnapshot(snapshotId);
   });

   before('Deploy Contracts', async() => {
       /* DEPLOY CONTRACTS HERE */
       exampleContract = await ExampleContract.new();
   });

   /* ADD TESTS HERE */

   it('Time Dependent Test', async () => {
       await timeMachine.advanceTimeAndBlock(/* SECONDS TO ADVANCE BY */);
   });
});

Methods

advanceTime(<seconds_to_advance_by>)

Advances the time on the blockchain forward. Takes a single parameter, which is the number of seconds to advance by. Note: for advancetime() to take effect, the block must also be mined using advanceBlock(). See advanceTimeAndBlock() to do both.

advanceBlock()

Mines a new block; advances the block forward by 1 block.

advanceBlockAndSetTime(<new_time>)

Advances the block forward by 1 and sets the time to a new time.

advanceTimeAndBlock(<seconds_to_advance_by>)

Advances the block by 1 in addition to advancing the time on the blockchain forward. Takes a single parameter, which is the number of seconds to advance by.

takeSnapshot()

Snapshot the state of the blockchain at the current block. Takes no parameters. Returns the integer id of the snapshot created.

revertToSnapshot(<id_to_revert_to>)

Revert the state of the blockchain to a previous snapshot. Takes a single parameter, which is the snapshot id to revert to.

Resources

• https://github.com/trufflesuite/ganache-cli
• https://www.trufflesuite.com
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