CODEWITHSUNDEEP
unit-testingethereumsolidity
RFV
RFV

Reputation: 839

Unit testing Datetime values

I have a function that makes use of the current time (now). The Contract as a whole is a Crowdfunding token and the cost of tokens differ depending on the date and time that tokens are purchased.

How does one simulate different times when testing a Smart Contract? For instance, with regards to the code below, I would like to do unit testing to find out if the code for setting price is correct but I can't change the value of now.

Would it be a good solution to simply substitute the now keyword for another temporary testing variable, say now_sim and then manually changing now_sim during simulation?

    if (now < (startTime + 1 days)) {
        currentPrice = safeDiv(safeMul(price, 80), 100);  // 20 % discount (x * 80 / 100)
    } 
    else if (now < (startTime + 2 days)) {
        currentPrice = safeDiv(safeMul(price, 90), 100);  // 10 % discount (x * 90 / 100)
    }
    else if (now < (startTime + 12 days)) {
        // 1 % reduction in the discounted rate from day 2 until day 12 (sliding scale per second)
        // 8640000 is 60 x 60 x 24 x 100 (100 for 1%) (60 x 60 x 24 for seconds per day)
        currentPrice = price - safeDiv(safeMul((startTime + 12 days) - now), price), 8640000);
    }
    else {
        currentPrice = price;
    }

Upvotes: 3

Views: 641

Answers (1)

RFV
RFV

Reputation: 839

If you use pyethereum for testing - which I highly recommend, it's lovely - you can directly alter the timestamp of the simulated block that is mining your transaction.

self.s = t.state()
self.s.block.timestamp = self.s.block.timestamp + 86400
self.s.mine(1)
some_val = your_contract.do_something(some_parameter)
self.assertEqual(some_val, whatever)

See a working example here (maybe a bit out-of-date): https://github.com/realitykeys/subjectivocracy/blob/master/contracts/test.py#L85

Upvotes: 3

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