test: Diff structured YAML when possible #8432
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
When we compare generated manifests against fixtures, we do a simple string comparison to compare output. The diffed data can be pretty hard to understand. This change adds a new test helper, `DiffTestYAML` that parses strings as arbitrary YAML data structures and uses `deep.Equal` to generate a diff of the datastructures. Now, when a test fails, we'll get output like: ``` install_test.go:244: YAML mismatches install_output.golden: slice[32].map[spec].map[template].map[spec].map[containers].slice[3].map[image]: PolicyControllerImageName:PolicyControllerVersion != SomeOtherImage:PolicyControllerVersion ``` While testing this, it became apparent that several of our generated golden files were not actually valid YAML, due to the `LinkerdVersion` value being unset. This has been fixed. Signed-off-by: Oliver Gould <ver@buoyant.io>
olix0r
force-pushed
the
ver/test-yaml-diff
branch
2 times, most recently
from
0b5f8da to
45b5798
Compare
adleong
approved these changes
May 6, 2022
There was a problem hiding this comment.
Nice!
If you wanted DiffTestYAML to take a testing.T, you could invoke https://pkg.go.dev/testing#T.Helper so that the comparison stack frame is skipped when reporting errors. But having it just return an error seems fine too.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
When we compare generated manifests against fixtures, we do a simple
string comparison. The diffed data can be pretty hard to understand.
This change adds a new test helper,
DiffTestYAMLthat parses stringsas arbitrary YAML data structures and uses
deep.Equalto generate adiff of the datastructures.
Now, when a test fails, we'll get output like:
While testing this, it became apparent that several of our generated
golden files were not actually valid YAML, due to the
LinkerdVersionvalue being unset. This has been fixed.
I opted to have
DiffTestYAMLreturn an error rather than take a*testing.Tparameter. When the test utility code invokest.Error*ort.Fatal*, the error is annotated as originating in the test utility and not in the actual test code. By returning an error that is handled in the test, we get a clearer signal of where the actual test failure occurred.This also means that commenting and whitespace changes won't be tested (which I think is probably good?)