go-testing

Define a slice of anonymous structs with name, input, want, and wantErr fields, then loop with t.Run(tt.name, ...) executing the function and asserting outputs and errors. Name cases by scenario rather than input mechanics for readable failure output.

Test Model.Update() directly by passing tea.Msg values like tea.KeyMsg and asserting the returned model's state transitions. Use teatest.NewTestModel() only for full interactive flows where you need to send messages and wait for the program to finish.

Direct Update() calls test pure state transitions synchronously and are fast and deterministic. teatest runs the full Bubbletea program loop, which suits end-to-end interactive flows but is slower and harder to debug.

Compare rendered output against a stored file, regenerating it only through a -update flag defined with flag.Bool. After updating, inspect the diff and rerun tests without -update to confirm the golden files match.

Wrap command execution behind small interfaces or mocks for unit tests. For real external commands, write integration tests guarded by testing.Short() so they are skipped when running go test with the -short flag.

t.TempDir creates an isolated temporary directory that Go cleans up automatically after the test, preventing cross-test pollution. It avoids relying on a real home directory, which makes tests non-deterministic across machines.