linkerd2/testutil/test_data_diff.go

124 lines
2.9 KiB
Go

package testutil
import (
"bytes"
"errors"
"fmt"
"io"
"io/ioutil"
"os"
"path/filepath"
"testing"
"github.com/go-test/deep"
"github.com/sergi/go-diff/diffmatchpatch"
"gopkg.in/yaml.v2"
)
// TestDataDiffer holds configuration for generating test diff
type TestDataDiffer struct {
PrettyDiff bool
UpdateFixtures bool
RejectPath string
}
// DiffTestYAML compares a YAML structure to a fixture on the filestystem.
func (td *TestDataDiffer) DiffTestYAML(path string, actualYAML string) error {
actual, err := unmarshalYAML([]byte(actualYAML))
if err != nil {
return fmt.Errorf("Failed to unmarshal generated YAML: %w", err)
}
expected, err := unmarshalYAML([]byte(ReadTestdata(path)))
if err != nil {
return fmt.Errorf("Failed to unmarshal generated YAML from %s: %w", path, err)
}
diff := deep.Equal(expected, actual)
if diff == nil {
return nil
}
td.storeActual(path, []byte(actualYAML))
e := fmt.Sprintf("YAML mismatches %s:", path)
for _, d := range diff {
e += fmt.Sprintf("\n %s", d)
}
return errors.New(e)
}
// DiffTestdata generates the diff for actual w.r.the file in path
func (td *TestDataDiffer) DiffTestdata(t *testing.T, path, actual string) {
expected := ReadTestdata(path)
if actual == expected {
return
}
dmp := diffmatchpatch.New()
diffs := dmp.DiffMain(expected, actual, true)
diffs = dmp.DiffCleanupSemantic(diffs)
var diff string
if td.PrettyDiff {
diff = dmp.DiffPrettyText(diffs)
} else {
diff = dmp.PatchToText(dmp.PatchMake(diffs))
}
t.Errorf("mismatch: %s\n%s", path, diff)
td.storeActual(path, []byte(actual))
}
func (td *TestDataDiffer) storeActual(path string, actual []byte) {
if td.UpdateFixtures {
writeTestdata(path, actual)
}
if td.RejectPath != "" {
writeRejects(path, actual, td.RejectPath)
}
}
// ReadTestdata reads a file and returns the contents of that file as a string.
func ReadTestdata(fileName string) string {
file, err := os.Open(filepath.Join("testdata", fileName))
if err != nil {
panic(fmt.Sprintf("Failed to open expected output file: %v", err))
}
fixture, err := ioutil.ReadAll(file)
if err != nil {
panic(fmt.Sprintf("Failed to read expected output file: %v", err))
}
return string(fixture)
}
func unmarshalYAML(data []byte) ([]interface{}, error) {
objs := make([]interface{}, 0)
rd := bytes.NewReader(data)
decoder := yaml.NewDecoder(rd)
for {
var obj interface{}
if err := decoder.Decode(&obj); err != nil {
if errors.Is(err, io.EOF) {
return objs, nil
}
return nil, err
}
objs = append(objs, obj)
}
}
func writeTestdata(fileName string, data []byte) {
p := filepath.Join("testdata", fileName)
if err := ioutil.WriteFile(p, data, 0600); err != nil {
panic(err)
}
}
func writeRejects(origFileName string, data []byte, rejectPath string) {
p := filepath.Join(rejectPath, origFileName+".rej")
if err := ioutil.WriteFile(p, data, 0600); err != nil {
panic(err)
}
}