Among the tasks developers hand to coding assistants, test generation produces the most consistent value. The reasons are structural properties of tests rather than anything about the model.
Why tests are a good fit
A test is verifiable immediately. It runs, and it passes or fails, which is feedback no implementation task provides so directly.
Tests are also formulaic, following an arrange, act and assert pattern that repeats endlessly across a codebase.
Repetitive work with an immediate correctness check is close to an ideal generation task, and it is the work developers most reliably postpone.
What the assistant sees that a developer misses
Given a function, an assistant enumerates edge cases mechanically: empty input, boundary values, wrong types, duplicate entries, unusual ordering.
Developers testing their own code test what they had in mind while writing it, which is precisely the set of cases that already work.
The value is less in the typing saved than in the enumeration, since the cases a developer would not have considered are the ones that find defects.
Why the risk is low
A wrong test fails visibly, and the cost of a bad test is the minutes spent deleting it.
Wrong implementation code merges quietly and surfaces later, so the two tasks carry very different consequences for the same error rate.
This asymmetry is the main argument for directing assistance towards tests first in a team that is still building confidence in the tooling.
Where the approach breaks
Generated tests assert what the code does rather than what it should do, so a test written against buggy code encodes the bug as expected behaviour.
Reading each assertion against the intended behaviour is therefore mandatory, and it is the step teams skip once the suite is green.
Tests generated in bulk also tend towards volume without coverage, producing many near-identical cases that lengthen the run and catch nothing new.
What it changes about test suites
Cheap test generation encourages large suites, and large suites are slow, which affects how often developers run them.
A suite nobody runs before pushing provides less protection than a smaller one that runs in seconds, so volume can reduce effective coverage.
Teams handling this well generate freely and then prune deliberately, treating the assistant as a source of candidate cases rather than as an author of the suite, which keeps the enumeration benefit without the maintenance cost.