In the context of software or information modeling, a happy path is a default scenario that features no exceptional or error conditions, and comprises the sequence of activities that will be executed if everything goes as expected.[1][2] For example, the "happy path" for a function that validates credit card numbers would be the one where none of the validation rules raise an error, thus letting execution continue successfully to the end, generating a positive response.
Happy path testing is a well-defined test case that uses known input, that executes without exception and that produces an expected output.
Happy day scenario and Golden path is a synonyms for happy path.