Testing with the Help of Test Helpers
Explore how to write test helper functions in Go that automate the creation and cleanup of test directories and files. Understand how to mark helpers for better error reporting, use cleanup functions, and verify file deletion efficiently. This lesson helps you develop reliable integration tests for file system operations in command-line tools.
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When we wrote the integration tests for the list functionality, we used the
testdata directory and a set of files to support our test cases. This procedure
works well when the directory structure doesn’t change. But if we want to
test file deletion, this might not be the best option because the files will be
deleted after the first test, and we would have to keep creating them for every
test run.
Instead, we automate the creation and cleanup of the test directory and files for
every test. In Go, we accomplish this by writing a test helper function and
calling this function from within each test. A test helper function is similar to
other functions, but we explicitly mark it as a test helper by calling the method
t.Helper() from the package testing. For example, when printing line and file
information, if the helper function fails with t.Fatal(), Go prints the line in the
test function that called the helper function, instead of within the helper function. This helps with troubleshooting test errors, particularly if the helper
function is called many times by different tests.
It’s also important to clean up after our tests. Cleaning up prevents wasting system resources and ensures that previous test’s artifacts don’t impact future tests. To clean up after these tests, our test helper function will return a cleanup function ...