This conversion is done by Transpec 2.2.1 with the following command:
transpec spec/unit
* 53 conversions
from: obj.should
to: expect(obj).to
* 19 conversions
from: == expected
to: eq(expected)
* 5 conversions
from: lambda { }.should
to: expect { }.to
* 2 conversions
from: be_true
to: be_truthy
For more details: https://github.com/yujinakayama/transpec#supported-conversions
