Testing of validate is done using the testdata directory.
Each directory under the testdata directory is a test case, containing an input.yaml and an errors.txt file.
The directory must contain these two files, or the test will fail.
input.yaml contains a YAML for an IngressRoute object, that will have the validation code run on it.
errors.txt should contain any warnings that should be emitted by the validation process.
If there should be no warnings, then errors.txt should be an empty file.