1 files changed, 164 insertions, 0 deletions
diff --git a/src/go/doc/doc_test.go b/src/go/doc/doc_test.go
new file mode 100644
index 0000000..cbdca62
--- /dev/null
+++ b/src/go/doc/doc_test.go
@@ -0,0 +1,164 @@
+// Copyright 2012 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package doc
+
+import (
+	"bytes"
+	"flag"
+	"fmt"
+	"go/ast"
+	"go/parser"
+	"go/printer"
+	"go/token"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strings"
+	"testing"
+	"text/template"
+)
+
+var update = flag.Bool("update", false, "update golden (.out) files")
+var files = flag.String("files", "", "consider only Go test files matching this regular expression")
+
+const dataDir = "testdata"
+
+var templateTxt = readTemplate("template.txt")
+
+func readTemplate(filename string) *template.Template {
+	t := template.New(filename)
+	t.Funcs(template.FuncMap{
+		"node":     nodeFmt,
+		"synopsis": synopsisFmt,
+		"indent":   indentFmt,
+	})
+	return template.Must(t.ParseFiles(filepath.Join(dataDir, filename)))
+}
+
+func nodeFmt(node interface{}, fset *token.FileSet) string {
+	var buf bytes.Buffer
+	printer.Fprint(&buf, fset, node)
+	return strings.ReplaceAll(strings.TrimSpace(buf.String()), "\n", "\n\t")
+}
+
+func synopsisFmt(s string) string {
+	const n = 64
+	if len(s) > n {
+		// cut off excess text and go back to a word boundary
+		s = s[0:n]
+		if i := strings.LastIndexAny(s, "\t\n "); i >= 0 {
+			s = s[0:i]
+		}
+		s = strings.TrimSpace(s) + " ..."
+	}
+	return "// " + strings.ReplaceAll(s, "\n", " ")
+}
+
+func indentFmt(indent, s string) string {
+	end := ""
+	if strings.HasSuffix(s, "\n") {
+		end = "\n"
+		s = s[:len(s)-1]
+	}
+	return indent + strings.ReplaceAll(s, "\n", "\n"+indent) + end
+}
+
+func isGoFile(fi fs.FileInfo) bool {
+	name := fi.Name()
+	return !fi.IsDir() &&
+		len(name) > 0 && name[0] != '.' && // ignore .files
+		filepath.Ext(name) == ".go"
+}
+
+type bundle struct {
+	*Package
+	FSet *token.FileSet
+}
+
+func test(t *testing.T, mode Mode) {
+	// determine file filter
+	filter := isGoFile
+	if *files != "" {
+		rx, err := regexp.Compile(*files)
+		if err != nil {
+			t.Fatal(err)
+		}
+		filter = func(fi fs.FileInfo) bool {
+			return isGoFile(fi) && rx.MatchString(fi.Name())
+		}
+	}
+
+	// get packages
+	fset := token.NewFileSet()
+	pkgs, err := parser.ParseDir(fset, dataDir, filter, parser.ParseComments)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// test packages
+	for _, pkg := range pkgs {
+		importPath := dataDir + "/" + pkg.Name
+		var files []*ast.File
+		for _, f := range pkg.Files {
+			files = append(files, f)
+		}
+		doc, err := NewFromFiles(fset, files, importPath, mode)
+		if err != nil {
+			t.Error(err)
+			continue
+		}
+
+		// golden files always use / in filenames - canonicalize them
+		for i, filename := range doc.Filenames {
+			doc.Filenames[i] = filepath.ToSlash(filename)
+		}
+
+		// print documentation
+		var buf bytes.Buffer
+		if err := templateTxt.Execute(&buf, bundle{doc, fset}); err != nil {
+			t.Error(err)
+			continue
+		}
+		got := buf.Bytes()
+
+		// update golden file if necessary
+		golden := filepath.Join(dataDir, fmt.Sprintf("%s.%d.golden", pkg.Name, mode))
+		if *update {
+			err := os.WriteFile(golden, got, 0644)
+			if err != nil {
+				t.Error(err)
+			}
+			continue
+		}
+
+		// get golden file
+		want, err := os.ReadFile(golden)
+		if err != nil {
+			t.Error(err)
+			continue
+		}
+
+		// compare
+		if !bytes.Equal(got, want) {
+			t.Errorf("package %s\n\tgot:\n%s\n\twant:\n%s", pkg.Name, got, want)
+		}
+	}
+}
+
+func Test(t *testing.T) {
+	test(t, 0)
+	test(t, AllDecls)
+	test(t, AllMethods)
+}
+
+func TestAnchorID(t *testing.T) {
+	const in = "Important Things 2 Know & Stuff"
+	const want = "hdr-Important_Things_2_Know___Stuff"
+	got := anchorID(in)
+	if got != want {
+		t.Errorf("anchorID(%q) = %q; want %q", in, got, want)
+	}
+}