A module can be built and seen to work, but seeing it work once is not the same as knowing it keeps working. Automated tests address that. This piece is about writing automated tests for an Odoo module.
What automated tests are
An automated test is a test, written as code, that checks that something works as it should, and that can be run, automatically, again and again. Writing automated tests for an Odoo module means writing tests that check the module's functionality genuinely works, and that can be run to check it, repeatedly. The tests are, in effect, a written, runnable confirmation that the module does what it should.
Why automated tests are worth writing
Automated tests are worth writing because of what they protect against: the module being broken by later changes without anyone noticing. A module, once built and seen to work, does not stay untouched; it is changed, extended, and the code around it changes too. A change, anywhere, can break something in the module, and break it quietly, without it being obvious. Automated tests catch that: because the tests can be run, again and again, after any change, they check, every time, that the module still genuinely works, and if a change has broken something, the tests find it. Without automated tests, breakage is found, if at all, by someone happening to notice it, perhaps long after, perhaps in genuine use. With them, breakage is caught, promptly, by the tests. Automated tests are, in essence, a guard that keeps checking the module works as it keeps being changed.
The value over time
The value of automated tests is, particularly, a value over time. When a module is first built, the developer sees it work; the tests add little that the developer does not already know at that moment. The value comes later, and keeps coming: every later change, to the module, to the code around it, in a new Odoo version, is checked by the tests, and breakage is caught. So automated tests are an investment, written once, and paying off over the whole life of the module, every time a change could have broken something. For a module that will genuinely be lived with and changed over time, that ongoing protection is genuinely worth the writing of the tests.
Tests are worth writing for genuine, meaningful checks
An honest note. Automated tests are worth writing when they genuinely check that the module's functionality works in meaningful ways, the genuine behaviour, the things that genuinely matter and could genuinely break. Tests that genuinely check the module's real functionality are a genuine guard; tests that are superficial or do not check anything meaningful are not. A developer writing automated tests should write them to genuinely check the module's real, meaningful functionality, so the tests are a genuine guard worth having.
The takeaway
Writing automated tests for an Odoo module creates tests, written as code, that check the module genuinely works and can be run, automatically, again and again. They are worth writing because they protect against the module being broken by later changes without anyone noticing: run after any change, the tests catch breakage promptly. Their value is over time, paying off every time a later change could have broken something, over the module's whole life. Write tests that genuinely check the module's real, meaningful functionality. For how we approach Odoo, see our ERP practice.