How-to Guides¶

Practical directions for common tasks. Each guide assumes you already have a working test suite — see the tutorial if you are starting from zero.

Testing¶

Guide	Goal
Skip tests temporarily	Disable a test or block without deleting it
Filter tests by name	Run a subset of tests during development
Run tests in CI	Integrate utest into a CI pipeline
Troubleshoot common problems	Diagnose and fix frequent failures
Reproduce a failing property	Automatically replay local failures and reproduce CI seeds

Guide	Goal
Mock a module with inject()	Scoped mock for code that receives a module as a parameter
Mock multiple modules at once	Inject two or more modules in a single call instead of nesting
Patch global state	Replace the module import itself for the duration of a test
Save and restore mock state	Checkpoint global mock state and roll it back after a test
Mock the filesystem	Intercept `fs` calls with virtual files
Mock a built-in global	Intercept `warn`, `system`, `print`, etc.
Mock UCI configuration	Provide test UCI packages without touching the real config
Mock ubus calls	Stub ubus object/method responses
Mock the event loop	Run timer callbacks synchronously without blocking
Mock HTTP requests	Return canned responses for outbound HTTP
Use strict mode	Fail loudly on any unmocked call
Write a custom proxy	Build a proxy for a module with no built-in support
Inspect calls with spy()	Assert which functions were called, with which arguments

Guide	Goal
Use combinators with assert.match()	Write flexible, composable assertions beyond exact equality

Guide	Goal
Add a built-in proxy	Ship a proxy for a new module inside the framework
Add an assertion	Extend the `assert` object with a new helper
Add a reporter	Add a new output format
Run the regression suite	Verify no examples regressed after a change