1

For instance I'm running testcase for a smart contract and it's test function has required validation.

function test(uint _id) public pure returns(bool){
    require(_id == 0 ,"not valid!");
    return true;
}

But when I execute the test case it throwing an error

AssertionError: Error: VM Exception while processing transaction: revert

Test cases:

it("Adding test into blockchain", async () => {                               

    const result = await Instance.test(1);                        

    expect(result).to.be.not.equal('null');            
});

it("Adding zero Id test into blockchain", async () => {                               

    const result = await Instance.test(0);                        

    //TODO: get error message   
});
  • what's your test block? – Badr Bellaj Jul 13 '18 at 8:25
  • @BadrBellaj: question updated! – Hina Khuman Jul 13 '18 at 8:32
1

Of course it will fire an exception

you have in the first test require(_id == 0 ,"not valid!");

and you feed it _id=1 (test(1)) therefore an exception will be raised.

either test with test(0)

or

check try/catch the exception as follow :

try {
     await Instance.test(1); 
        } catch (error) {
            Error = error;
        }
        assert.notEqual(Error, undefined, 'Error must be thrown');
        assert.isAbove(Error.message.search('VM Exception while processing transaction: revert'), -1, 'Error: VM Exception while processing transaction: revert');

    });
  • either test with test(0), but I want to create negative test(s) to make sure smart contract would handle the things appropriately. check try/catch the exception any example would be really helpful, currently I added catch block, though it gives an exception. – Hina Khuman Jul 13 '18 at 10:33
  • I also tried to make library like this but seems import having issue with truffle.. don't know how other implemented. – Hina Khuman Jul 13 '18 at 10:38
  • check the try/catch block i've proposed – Badr Bellaj Jul 13 '18 at 10:40
  • 1
    what's awful in it? :p you raise an error and you check the message nothing harmfull – Badr Bellaj Jul 13 '18 at 10:52
  • 2
    What if you have a stack of require statements and want to test which one triggered during a test. Without the message it seems impossible. Also, if you can't get the require message, what purpose does it even serve? – Justin Jul 13 '18 at 14:59

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