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Ethereum: Unknown selector error (0x98296c54) in BIGTTokenTest.t.sol

The latest iteration of the popular smart contract testing framework, testbobBalance, has encountered an unexpected error. The specific issue involves an “Unknown selector” error that is triggered when running a test using the BIGTTokenTest contract.

Issue: Unknown selector error (0x98296c54)

This unknown selector error occurs when attempting to access the VmCalls function within the testbobBalance test. The error message “Unknown selector 0x98296c54 for VmCalls” indicates that there is a problem with the way the contract functions are called.

Source code: BIGTTokenTest.t.sol

After reviewing the code, it appears that the testbobBalance function within the BIGTTokenTest contract contains a logical error. Specifically, the test attempts to call the VmCalls function with an argument that is not defined in the current scope.

Problematic line of code

function testbobBalance() public {
// ... (other code)
VmCalls(vb, 0x0 }

In this line of code, VmCalls is called with the argument 0x0 Here is an updated version of the code snippet with the corrected line:

function testbobBalance() public {
// ... (other code)
VmCalls(vb, 0x0 }

By adding a second argument 0x0