code: public function addMockResult(int $exitCode, string $stdOut, string $stdErr): CommandBuilderInterface
      {
          $mockResultList = $this->mockResultList;
          $mockResultList[] = new ProcessOutput($exitCode, $stdOut, $stdErr);
  
          return new MockCommandBuilder(
              $mockResultList,
              $this->command,
              $this->argumentList,
              $this->timeout,
              $this->pollTimeout,
              $this->cwd,
              $this->envVariableList,
              $this->builtCommandList
          );
      }
docs: Add a mock result (to be returned in order of execution).
  
  @param int $exitCode
  @param string $stdOut
  @param string $stdErr
  
  @return $this