open-consul/agent/xds/golden_test.go

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// Copyright (c) HashiCorp, Inc.
// SPDX-License-Identifier: MPL-2.0
package xds
import (
"encoding/json"
"flag"
"fmt"
"os"
"path/filepath"
"testing"
"github.com/hashicorp/go-version"
"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
"google.golang.org/protobuf/encoding/protojson"
"google.golang.org/protobuf/proto"
)
// update allows golden files to be updated based on the current output.
var update = flag.Bool("update", false, "update golden files")
// goldenSimple is just for read/write access to a golden file that is not
// envoy specific.
func goldenSimple(t *testing.T, name, got string) string {
return golden(t, name, "", "", got)
}
// goldenEnvoy is a special variant of golden() that silos each named test by
// each supported envoy version
func goldenEnvoy(t *testing.T, name, envoyVersion, latestEnvoyVersion, got string) string {
t.Helper()
require.NotEmpty(t, envoyVersion)
// We'll need both the name of this golden file for the requested version
// of envoy AND the latest version of envoy due to how the golden file
// coalescing works below when there is no xDS generated skew across envoy
// versions.
subname := goldenEnvoyVersionName(t, envoyVersion)
latestSubname := "latest"
if envoyVersion == latestEnvoyVersion {
subname = "latest"
}
return golden(t, name, subname, latestSubname, got)
}
func goldenEnvoyVersionName(t *testing.T, envoyVersion string) string {
t.Helper()
require.NotEmpty(t, envoyVersion)
// We do version sniffing on the complete version, but only generate
// golden files ignoring the patch portion
version := version.Must(version.NewVersion(envoyVersion))
segments := version.Segments()
require.Len(t, segments, 3)
return fmt.Sprintf("envoy-%d-%d-x", segments[0], segments[1])
}
// golden reads and optionally writes the expected data to the golden file,
// returning the contents as a string.
//
// The golden file is named with two components the "name" and the "subname".
// In the common case of xDS tests the "name" component is the logical name of
// the test itself, and the "subname" is derived from the envoy major version.
//
// If latestSubname is specified we use that as a fallback source of comparison
// if the specific golden file referred to by subname is absent.
//
// If the -update flag is passed when executing the tests then the contents of
// the "got" argument are written to the golden file on disk. If the
// latestSubname argument is specified in this mode and the generated content
// matches that of the latest generated content then the specific golden file
// referred to by 'subname' is deleted to avoid unnecessary duplication in the
// testdata directory.
func golden(t *testing.T, name, subname, latestSubname, got string) string {
t.Helper()
suffix := ".golden"
if subname != "" {
suffix = fmt.Sprintf(".%s.golden", subname)
}
golden := filepath.Join("testdata", name+suffix)
var latestGoldenPath, latestExpected string
isLatest := subname == latestSubname
// Include latestSubname in the latest golden path if it exists.
if latestSubname == "" {
latestGoldenPath = filepath.Join("testdata", fmt.Sprintf("%s.golden", name))
} else {
latestGoldenPath = filepath.Join("testdata", fmt.Sprintf("%s.%s.golden", name, latestSubname))
}
if raw, err := os.ReadFile(latestGoldenPath); err == nil {
latestExpected = string(raw)
}
// Handle easy updates to the golden files in the agent/xds/testdata
// directory.
//
// To trim down PRs, we only create per-version golden files if they differ
// from the latest version.
if *update && got != "" {
var gotInterface, latestExpectedInterface interface{}
json.Unmarshal([]byte(got), &gotInterface)
json.Unmarshal([]byte(latestExpected), &latestExpectedInterface)
// Remove non-latest golden files if they are the same as the latest one.
if !isLatest && assert.ObjectsAreEqualValues(gotInterface, latestExpectedInterface) {
// In update mode we erase a golden file if it is identical to
// the golden file corresponding to the latest version of
// envoy.
err := os.Remove(golden)
if err != nil && !os.IsNotExist(err) {
require.NoError(t, err)
}
return got
}
// We use require.JSONEq to compare values and ObjectsAreEqualValues is used
// internally by that function to compare the string JSON values. This only
// writes updates the golden file when they actually change.
if !assert.ObjectsAreEqualValues(gotInterface, latestExpectedInterface) {
require.NoError(t, os.WriteFile(golden, []byte(got), 0644))
}
return got
}
expected, err := os.ReadFile(golden)
if latestExpected != "" && os.IsNotExist(err) {
// In readonly mode if a specific golden file isn't found, we fallback
// on the latest one.
return latestExpected
}
require.NoError(t, err)
return string(expected)
}
func protoToJSON(t *testing.T, pb proto.Message) string {
t.Helper()
m := protojson.MarshalOptions{
Indent: " ",
}
gotJSON, err := m.Marshal(pb)
require.NoError(t, err)
return string(gotJSON)
}