Remix Unit Tests

result.txt

        ◼  MyTest
[02:35:23] payload method is  eth_gasPrice
[02:35:23] payload method is  eth_sendTransaction
[02:35:23] payload method is  eth_getTransactionReceipt
[02:35:23] payload method is  eth_gasPrice
[02:35:23] payload method is  eth_sendTransaction
[02:35:23] payload method is  eth_getTransactionReceipt
[02:35:23] payload method is  eth_gasPrice
[02:35:23] payload method is  eth_sendTransaction
[02:35:23] payload method is  eth_getTransactionReceipt
        ✓  Initial value should be100
[02:35:23] payload method is  eth_gasPrice
[02:35:23] payload method is  eth_sendTransaction
[02:35:23] payload method is  eth_getTransactionReceipt
[02:35:23] payload method is  eth_call
        ✓  Initial value should be200


  2 passing (1s)

simple_storage.sol

pragma solidity ^0.5.0;
contract SimpleStorage {
   uint public storedData;

   constructor() public {
      storedData = 100;
   }

   function set(uint x) public {
      storedData = x;
   }

   function get() public view returns (uint retVal) {
      return storedData;
   }

}

simple_storage_test.sol

pragma solidity ^0.5.0;
import "./simple_storage.sol";

contract MyTest {
  SimpleStorage foo;
  uint i = 0;

  function beforeAll() public {
    foo = new SimpleStorage();
  }

  function beforeEach() public {
    if (i == 1) {
      foo.set(200);
    }
    i += 1;
  }

  function initialValueShouldBe100() public {
    Assert.equal(foo.get(), 100, "initial value is not correct");
  }

  function initialValueShouldBe200() public view returns (bool) {
    return foo.get() == 200;
  }
}