Testing address(this) generates exception, how to obtain the correct value for address(this)

Question

I have modified the following code from a michalzalecki website https://michalzalecki.com/ethereum-test-driven-introduction-to-solidity/ to test address(this):

pragma solidity 0.5.16;
import "truffle/Assert.sol";
import "../contracts/Funding.sol";
import "truffle/DeployedAddresses.sol";

contract FundingTest {
  address v = 0xBFF7fd8064C448347e239FD7B7347b6D959Fb9f2;
  function testSettingAnOwnerOfDeployedContract() public {
    Funding funding = Funding(DeployedAddresses.Funding());
    //Assert.equal(funding.owner(), address(this), "An owner is different than a deployer");
    //Assert.equal(funding.owner(), msg.sender , "An owner is different than a deployer");
    Assert.equal(v, address(this), "An owner is different than a deployer");

  }
}

My contract code is:

pragma solidity 0.5.16;

contract Funding {
  address public owner;
  constructor() public {
     owner = msg.sender;
  }
}

When I run the truffle migrate, I got following addresses:

1_initial_migration.js
======================

   Deploying 'Migrations'
   ----------------------
   > transaction hash:    0x59d01a9d031010d4b0cc7d0d7db87d8d7c5d2a96f9ec1117512c1ec73e578321
   > Blocks: 0            Seconds: 0
   > contract address:    0x258B8538F1dA81DC872A21f38782B548BA849efc
   > block number:        1
   > block timestamp:     1631809265
   > account:             0x05A4de8a003419dF5e51fF20D36750e990a32C1e


2_deploy_contracts.js
=====================

   Deploying 'Funding'
   -------------------
   > transaction hash:    0xbbe3ba94cc623931990c1b802ced466b7854378a89c02c5d3adf0742b8a571aa
   > Blocks: 0            Seconds: 0
   > contract address:    0xBFF7fd8064C448347e239FD7B7347b6D959Fb9f2
   > block number:        3
   > block timestamp:     1631809266
   > account:             0x05A4de8a003419dF5e51fF20D36750e990a32C1e
   > balance:             99.99291392

I am getting the following exception message when I run the truffle test:

$ truffle test
Using network 'development'.
   
    /home/zulfi/Truffle_programs/michal-unboxRem/test/FundingTest.sol:9:5: Warning: Unused local variable.
    Funding funding = Funding(DeployedAddresses.Funding());
    ^-------------^

> Artifacts written to /tmp/test--7766-a2isLlv7uM20
> Compiled successfully using:
   - solc: 0.5.16+commit.9c3226ce.Emscripten.clang



  FundingTest
    1) testSettingAnOwnerOfDeployedContract
    > No events were emitted


  0 passing (6s)
  1 failing

  1) FundingTest
       testSettingAnOwnerOfDeployedContract:
     Error: An owner is different than a deployer
      at checkResultForFailure (/home/zulfi/.nvm/versions/node/v10.23.3/lib/node_modules/truffle/build/webpack:/packages/core/lib/testing/SolidityTest.js:66:1)
      at process._tickCallback (internal/process/next_tick.js:68:7)

Somebody please guide how to avoid the exception, how to retrieve the correct value of address(this), why migration value does not work?

Zulfi.

Answer 1

address(this) will return the address of the FundingTest contract, so of course it will be different from the Funding contract. The test should pass if you use address(funding), assuming your address for v is correct.