phodal/coca

package cocatest

// based on https://github.com/helm/helm
// license: apache 2.0
// just copy

import (
    "bytes"
    "flag"
    "github.com/pkg/errors"
    "io/ioutil"
    "path/filepath"
    "runtime"
)

// UpdateGolden writes out the Golden files with the latest values, rather than failing the test.
var updateGolden = flag.Bool("update", false, "update Golden files")

// TestingT describes a testing object compatible with the critical functions from the testing.T type
type TestingT interface {
    Fatal(...interface{})
    Fatalf(string, ...interface{})
    HelperT
}

// HelperT describes a test with a helper function
type HelperT interface {
    Helper()
}

// AssertGoldenBytes asserts that the give actual content matches the contents of the given filename
func AssertGoldenBytes(t TestingT, actual []byte, filename string) {
    t.Helper()

    if err := compare(actual, path(filename)); err != nil {
        t.Fatalf("%v", err)
    }
}

// AssertGoldenString asserts that the given string matches the contents of the given file.
func AssertGoldenString(t TestingT, actual, filename string) {
    t.Helper()

    if err := compare([]byte(actual), path(filename)); err != nil {
        t.Fatalf("%v", err)
    }
}

// AssertGoldenFile assers that the content of the actual file matches the contents of the expected file
func AssertGoldenFile(t TestingT, actualFileName string, expectedFilename string) {
    t.Helper()

    actual, err := ioutil.ReadFile(actualFileName)
    if err != nil {
        t.Fatalf("%v", err)
    }
    AssertGoldenBytes(t, actual, expectedFilename)
}

func path(filename string) string {
    if filepath.IsAbs(filename) {
        return filename
    }
    return filepath.Join("", filename)
}

func compare(actual []byte, filename string) error {
    if err := update(filename, actual); err != nil {
        return err
    }

    expected, err := ioutil.ReadFile(filename)
    if err != nil {
        return errors.Wrapf(err, "unable to read testdata %s", filename)
    }

    // TODO: fix path test for Windows...
    if runtime.GOOS == "windows" {
        return nil
    }

    if !bytes.Equal(expected, actual) {
        return errors.Errorf("does not match Golden file %s\n\nWANT:\n'%s'\n\nGOT:\n'%s'\n", filename, expected, actual)
    }
    return nil
}

func update(filename string, in []byte) error {
    if !*updateGolden {
        return nil
    }
    return ioutil.WriteFile(filename, normalize(in), 0666)
}

func normalize(in []byte) []byte {
    return bytes.Replace(in, []byte("\r\n"), []byte("\n"), -1)
}