An employment contract is considered a contract for an unlimited period effective from the day of its commencement in any of the following cases:
1.If it is not concluded in writing .
2. If it is made for an unlimited period.
3. If it is made in writing for a limited period and continues to be applied by both parties after lapse of its period without a written agreement between them.
4. If it is concluded for the performance of a specific job for which no period is fixed, or if the job by its nature calls for renewal, and has remained in force despite the completion of work agreed to.