Time-dependent test unexpected behavior at 1st attempt, expected behavior at 2nd attempt

Question

I'm trying to test a contract in which functions should require certain timestamps. Parts of code are eliminated for readability:

Here's the problematic part of the contract :

PCE_Contract.sol

pragma solidity ^0.7.0;

contract PCE_Contract{

constructor(uint256 newStartTime, uint256 PERIOD)
{
_PERIOD     = PERIOD * 1 days  ;
 initiation = newStartTime     ;
}

 function enter() payable public
  { 
    require(( block.timestamp < (initiation + _PERIOD) ),
     "Period for this function has ended." );
    // do stuff
  }
}

I'm simulating time using the info found in this article.

PCE_Contract_test.js

const expected_period           = 7     ;
const SECONDS_IN_DAY            = 86400 ;

const Mon_01_Jun_00_00_UTC_2020 = 1590969600; // 06-01-2020 @ 12.00 am (UTC)
const Mon_09_Jun_13_00_UTC_2020 = 1591660800; // 06-09-2020 @ 01.00 pm (UTC) 

contract('PCE_Contract', async (accounts) =>
{ 
  before( async () => {
  
    instance_1 = await PCE_Contract.new(Mon_01_Jun_00_00_UTC_2020 ,expected_period );
    instance_2 = await PCE_Contract.new(Mon_09_Jun_13_00_UTC_2020 ,expected_period );
  });
const expected_address          = accounts[1];

// more tests using instance_1

  it("No entry after period is over, OK", async() => 
  {
    await test_helper.advanceTimeAndBlock(SECONDS_IN_DAY * (expected_period ));

    await instance_2.enter({ from: expected_address, value: String(1e18)});
  
  });

}

I expected the test to fail, since _PERIOD time has passed since instance_1. However, in the first test run the test passes. The interesting part is that when I run the test for a second time (which will start from the timestamp 1st test ended at) The test fails (expected behavior).

Why does the 1st test's time-simulation fail even though I can see time has passed in ganache-cli ? How can I fix the issue so that I can test functions in two time periods ?

ganache-cli output for two tests that have time-jump between:

  Transaction: 0xbb9e5b0e3ee1bc266d79ebe169061259c4832cbbc175b63ff1719aa125cf06a3
  Gas usage: 40655
  Block Number: 10
  Block Time: Mon Jun 01 2020 03:00:24 GMT+0300 (GMT+03:00)
  Runtime Error: revert
  Revert reason: ERROR

eth_call
eth_blockNumber
evm_increaseTime
evm_mine
eth_getBlockByNumber
eth_getBlockByNumber
eth_getBlockByNumber
eth_sendTransaction

  Transaction: 0x43578162490a3edf734c17462056f2090b3775a2a90228a0097da53c42319afb
  Gas usage: 112357
  Block Number: 12
  Block Time: Tue Jun 09 2020 03:00:24 GMT+0300 (GMT+03:00) 

Truffle v5.1.49
Ganache CLI v6.12.1 (ganache-core: 2.13.1)
Node v12.18.4

Answer 1

The code sets instance_1 initiation to June 1, and instance_2 initiation to June 9.

In the logs the time has advanced to June 9. So tests should fail for instance_1 but succeed for instance_2.

Since the test checks for instance_2 it is correct for the test to succeed.