/
txtar.go
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/
txtar.go
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// Copyright 2020 CUE Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package cuetxtar
import (
"bufio"
"bytes"
"fmt"
"io"
"io/fs"
"os"
"path"
"path/filepath"
"strings"
"testing"
"cuelang.org/go/cue/ast"
"cuelang.org/go/cue/build"
"cuelang.org/go/cue/errors"
"cuelang.org/go/cue/format"
"cuelang.org/go/cue/load"
"cuelang.org/go/internal/cuetest"
"github.com/google/go-cmp/cmp"
"github.com/rogpeppe/go-internal/diff"
"golang.org/x/tools/txtar"
)
// A TxTarTest represents a test run that process all CUE tests in the txtar
// format rooted in a given directory. See the [Test] documentation for
// more details.
type TxTarTest struct {
// Run TxTarTest on this directory.
Root string
// Name is a unique name for this test. The golden file for this test is
// derived from the out/<name> file in the .txtar file.
//
// TODO: by default derive from the current base directory name.
Name string
// Fallback allows the golden tests named by Fallback to pass tests in
// case the golden file corresponding to Name does not exist.
// The feature can be used to have two implementations of the same
// functionality share the same test sets.
Fallback string
// Skip is a map of tests to skip; the key is the test name; the value is the
// skip message.
Skip map[string]string
// ToDo is a map of tests that should be skipped now, but should be fixed.
ToDo map[string]string
// LoadConfig is passed to load.Instances when loading instances.
// It's copied before doing that and the Dir and Overlay fields are overwritten.
LoadConfig load.Config
}
// A Test represents a single test based on a .txtar file.
//
// A Test embeds *[testing.T] and should be used to report errors.
//
// Entries within the txtar file define CUE files (available via the
// Instances and RawInstances methods) and expected output
// (or "golden") files (names starting with "out/\(testname)"). The "main" golden
// file is "out/\(testname)" itself, used when [Test] is used directly as an [io.Writer]
// and with [Test.WriteFile].
//
// When the test function has returned, output written with [Test.Write], [Test.Writer]
// and friends is checked against the expected output files.
//
// A txtar file can define test-specific tags and values in the comment section.
// These are available via the [Test.HasTag] and [Test.Value] methods.
// The #skip tag causes a [Test] to be skipped.
// The #noformat tag causes the $CUE_FORMAT_TXTAR value
// to be ignored.
//
// If the output differs and $CUE_UPDATE is non-empty, the txtar file will be
// updated and written to disk with the actual output data replacing the
// out files.
//
// If $CUE_FORMAT_TXTAR is non-empty, any CUE files in the txtar
// file will be updated to be properly formatted, unless the #noformat
// tag is present.
type Test struct {
// Allow Test to be used as a T.
*testing.T
prefix string
fallback string
buf *bytes.Buffer // the default buffer
outFiles []file
Archive *txtar.Archive
LoadConfig load.Config
// The absolute path of the current test directory.
Dir string
hasGold bool
}
// Write implements [io.Writer] by writing to the output for the test,
// which will be tested against the main golden file.
func (t *Test) Write(b []byte) (n int, err error) {
if t.buf == nil {
t.buf = &bytes.Buffer{}
t.outFiles = append(t.outFiles, file{t.prefix, t.fallback, t.buf, false})
}
return t.buf.Write(b)
}
type file struct {
name string
fallback string
buf *bytes.Buffer
diff bool // true if this contains a diff between fallback and main
}
// HasTag reports whether the tag with the given key is defined
// for the current test. A tag x is defined by a line in the comment
// section of the txtar file like:
//
// #x
func (t *Test) HasTag(key string) bool {
prefix := []byte("#" + key)
s := bufio.NewScanner(bytes.NewReader(t.Archive.Comment))
for s.Scan() {
b := s.Bytes()
if bytes.Equal(bytes.TrimSpace(b), prefix) {
return true
}
}
return false
}
// Value returns the value for the given key for this test and
// reports whether it was defined.
//
// A value is defined by a line in the comment section of the txtar
// file like:
//
// #key: value
//
// White space is trimmed from the value before returning.
func (t *Test) Value(key string) (value string, ok bool) {
prefix := []byte("#" + key + ":")
s := bufio.NewScanner(bytes.NewReader(t.Archive.Comment))
for s.Scan() {
b := s.Bytes()
if bytes.HasPrefix(b, prefix) {
return string(bytes.TrimSpace(b[len(prefix):])), true
}
}
return "", false
}
// Bool searches for a line starting with #key: value in the comment and
// reports whether the key exists and its value is true.
func (t *Test) Bool(key string) bool {
s, ok := t.Value(key)
return ok && s == "true"
}
// Rel converts filename to a normalized form so that it will given the same
// output across different runs and OSes.
func (t *Test) Rel(filename string) string {
rel, err := filepath.Rel(t.Dir, filename)
if err != nil {
return filepath.Base(filename)
}
return filepath.ToSlash(rel)
}
// WriteErrors writes the full list of errors in err to the test output.
func (t *Test) WriteErrors(err errors.Error) {
if err != nil {
errors.Print(t, err, &errors.Config{
Cwd: t.Dir,
ToSlash: true,
})
}
}
// WriteFile formats f and writes it to the main output,
// prefixed by a line of the form:
//
// == name
//
// where name is the base name of f.Filename.
func (t *Test) WriteFile(f *ast.File) {
// TODO: use FileWriter instead in separate CL.
fmt.Fprintln(t, "==", filepath.Base(f.Filename))
_, _ = t.Write(formatNode(t.T, f))
}
// Writer returns a Writer with the given name. Data written will
// be checked against the file with name "out/\(testName)/\(name)"
// in the txtar file. If name is empty, data will be written to the test
// output and checked against "out/\(testName)".
func (t *Test) Writer(name string) io.Writer {
var fallback string
switch name {
case "":
name = t.prefix
fallback = t.fallback
default:
fallback = path.Join(t.fallback, name)
name = path.Join(t.prefix, name)
}
for _, f := range t.outFiles {
if f.name == name {
return f.buf
}
}
w := &bytes.Buffer{}
t.outFiles = append(t.outFiles, file{name, fallback, w, false})
if name == t.prefix {
t.buf = w
}
return w
}
func formatNode(t *testing.T, n ast.Node) []byte {
t.Helper()
b, err := format.Node(n)
if err != nil {
t.Fatal(err)
}
return b
}
// Instance returns the single instance representing the
// root directory in the txtar file.
func (t *Test) Instance() *build.Instance {
t.Helper()
return t.Instances()[0]
}
// Instances returns the valid instances for this .txtar file or skips the
// test if there is an error loading the instances.
func (t *Test) Instances(args ...string) []*build.Instance {
t.Helper()
a := t.RawInstances(args...)
for _, i := range a {
if i.Err != nil {
if t.hasGold {
t.Fatal("Parse error: ", errors.Details(i.Err, nil))
}
t.Skip("Parse error: ", errors.Details(i.Err, nil))
}
}
return a
}
// RawInstances returns the intstances represented by this .txtar file. The
// returned instances are not checked for errors.
func (t *Test) RawInstances(args ...string) []*build.Instance {
return loadWithConfig(t.Archive, t.Dir, t.LoadConfig, args...)
}
// Load loads the intstances of a txtar file. By default, it only loads
// files in the root directory. Relative files in the archive are given an
// absolute location by prefixing it with dir.
func Load(a *txtar.Archive, dir string, args ...string) []*build.Instance {
// Don't let Env be nil, as the tests shouldn't depend on os.Environ.
return loadWithConfig(a, dir, load.Config{Env: []string{}}, args...)
}
func loadWithConfig(a *txtar.Archive, dir string, cfg load.Config, args ...string) []*build.Instance {
auto := len(args) == 0
overlay := map[string]load.Source{}
for _, f := range a.Files {
if auto && !strings.Contains(f.Name, "/") {
args = append(args, f.Name)
}
overlay[filepath.Join(dir, f.Name)] = load.FromBytes(f.Data)
}
cfg.Dir = dir
cfg.Overlay = overlay
return load.Instances(args, &cfg)
}
// Run runs tests defined in txtar files in x.Root or its subdirectories.
//
// The function f is called for each such txtar file. See the [Test] documentation
// for more details.
func (x *TxTarTest) Run(t *testing.T, f func(tc *Test)) {
t.Helper()
dir, err := os.Getwd()
if err != nil {
t.Fatal(err)
}
root := x.Root
err = filepath.WalkDir(root, func(fullpath string, entry fs.DirEntry, err error) error {
if err != nil {
return err
}
if entry.IsDir() || filepath.Ext(fullpath) != ".txtar" {
return nil
}
str := filepath.ToSlash(fullpath)
p := strings.Index(str, "/testdata/")
testName := str[p+len("/testdata/") : len(str)-len(".txtar")]
t.Run(testName, func(t *testing.T) {
a, err := txtar.ParseFile(fullpath)
if err != nil {
t.Fatalf("error parsing txtar file: %v", err)
}
tc := &Test{
T: t,
Archive: a,
Dir: filepath.Dir(filepath.Join(dir, fullpath)),
prefix: path.Join("out", x.Name),
LoadConfig: x.LoadConfig,
}
// Don't let Env be nil, as the tests shouldn't depend on os.Environ.
if tc.LoadConfig.Env == nil {
tc.LoadConfig.Env = []string{}
}
if x.Fallback != "" {
tc.fallback = path.Join("out", x.Fallback)
} else {
tc.fallback = tc.prefix
}
if tc.HasTag("skip") {
t.Skip()
}
if msg, ok := x.Skip[testName]; ok {
t.Skip(msg)
}
if msg, ok := x.ToDo[testName]; ok {
t.Skip(msg)
}
update := false
for i, f := range a.Files {
hasPrefix := func(s string) bool {
// It's either "\(tc.prefix)" or "\(tc.prefix)/..." but not some other name
// that happens to start with tc.prefix.
return strings.HasPrefix(f.Name, s) && (f.Name == s || f.Name[len(s)] == '/')
}
tc.hasGold = hasPrefix(tc.prefix) || hasPrefix(tc.fallback)
// Format CUE files as required
if tc.HasTag("noformat") || !strings.HasSuffix(f.Name, ".cue") {
continue
}
if ff, err := format.Source(f.Data); err == nil {
if bytes.Equal(f.Data, ff) {
continue
}
if cuetest.FormatTxtar {
update = true
a.Files[i].Data = ff
}
}
}
f(tc)
index := make(map[string]int, len(a.Files))
for i, f := range a.Files {
index[f.Name] = i
}
// Add diff files between fallback and main file. These are added
// as regular output files so that they can be updated as well.
for _, sub := range tc.outFiles {
if sub.fallback == sub.name {
continue
}
if j, ok := index[sub.fallback]; ok {
fallback := a.Files[j].Data
result := sub.buf.Bytes()
if len(result) == 0 || len(fallback) == 0 {
continue
}
diff := diff.Diff("old", fallback, "new", result)
if len(diff) == 0 {
continue
}
tc.outFiles = append(tc.outFiles, file{
name: "diff/-" + sub.name + "<==>+" + sub.fallback,
buf: bytes.NewBuffer(diff),
diff: true,
})
}
}
// Insert results of this test at first location of any existing
// test or at end of list otherwise.
k := len(a.Files)
for _, sub := range tc.outFiles {
if i, ok := index[sub.name]; ok {
k = i
break
}
if i, ok := index[sub.fallback]; ok {
k = i
break
}
}
files := a.Files[:k:k]
for _, sub := range tc.outFiles {
result := sub.buf.Bytes()
files = append(files, txtar.File{Name: sub.name})
gold := &files[len(files)-1]
if i, ok := index[sub.name]; ok {
gold.Data = a.Files[i].Data
delete(index, sub.name)
if bytes.Equal(gold.Data, result) {
continue
}
} else if i, ok := index[sub.fallback]; ok {
gold.Data = a.Files[i].Data
// Use the golden file of the fallback set if it matches.
if bytes.Equal(gold.Data, result) {
gold.Name = sub.fallback
delete(index, sub.fallback)
continue
}
}
if cuetest.UpdateGoldenFiles {
update = true
gold.Data = result
continue
}
// Skip the test if just the diff differs.
// TODO: also fail once diffs are fully in use.
if sub.diff {
continue
}
t.Errorf("result for %s differs: (-want +got)\n%s",
sub.name,
cmp.Diff(string(gold.Data), string(result)),
)
t.Errorf("actual result: %q", result)
}
// Add remaining unrelated files, ignoring files that were already
// added.
for _, f := range a.Files[k:] {
if _, ok := index[f.Name]; ok {
files = append(files, f)
}
}
a.Files = files
if update {
err = os.WriteFile(fullpath, txtar.Format(a), 0644)
if err != nil {
t.Fatal(err)
}
}
})
return nil
})
if err != nil {
t.Fatal(err)
}
}