ESP-IDF unit tests are run using Unit Test App. The app can be built with the unit tests for a specific component. Unit tests are in test subdirectories of respective components.

Building Unit Test App

Follow the setup instructions in the top-level esp-idf README.
Set IDF_PATH environment variable to point to the path to the esp-idf top-level directory.
Change into tools/unit-test-app directory
make menuconfig to configure the Unit Test App.
make TEST_COMPONENTS= with TEST_COMPONENTS set to names of the components to be included in the test app. Or make TESTS_ALL=1 to build the test app with all the tests for components having test subdirectory.
Follow the printed instructions to flash, or run make flash.

Running Unit Tests

The unit test loader will prompt by showing a menu of available tests to run:

Type a number to run a single test.
* to run all tests.
[tagname] to run tests with "tag"
![tagname] to run tests without "tag" (![ignore] is very useful as it runs all CI-enabled tests.)
"test name here" to run test with given name