Package golden testing with golden files in Go. A golden file is the expected output of test, stored as a separate file rather than as a string literal inside the test code. So when the test is executed, it will read data from the file and compare it to the output produced by the functionality under test.
When writing unit tests, there comes a point when you need to check that the complex output of a function matches your expectations. This could be binary data (like an Image, JSON, HTML etc). Golden files are a way of ensuring your function output matches its .golden file. It’s a pattern used in the Go standard library.
One of the advantages of the gold files approach is that you can easily update the test data using the command line flag without copying the data into the text variables of go this is very convenient in case of significant changes in the behavior of the system but also requires attention to the changed test data and checking the correctness of the new golden results.
A special cli is provided in the package. The special flag -update is
provided in the package for conveniently updating ethos files, for example,
using the following command:
go test ./... -update
Golden files are placed in directory testdata this directory is ignored by
the standard tools go, and it can accommodate a variety of data used in test or
samples.
go get github.com/xorcare/golden