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// Copyright 2013 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_test
import (
"bytes"
"fmt"
"go/ast"
"go/doc"
"go/format"
"go/parser"
"go/token"
"reflect"
"strings"
"testing"
)
const exampleTestFile = `
package foo_test
import (
"flag"
"fmt"
"log"
"sort"
"os/exec"
)
func ExampleHello() {
fmt.Println("Hello, world!")
// Output: Hello, world!
}
func ExampleImport() {
out, err := exec.Command("date").Output()
if err != nil {
log.Fatal(err)
}
fmt.Printf("The date is %s\n", out)
}
func ExampleKeyValue() {
v := struct {
a string
b int
}{
a: "A",
b: 1,
}
fmt.Print(v)
// Output: a: "A", b: 1
}
func ExampleKeyValueImport() {
f := flag.Flag{
Name: "play",
}
fmt.Print(f)
// Output: Name: "play"
}
var keyValueTopDecl = struct {
a string
b int
}{
a: "B",
b: 2,
}
func ExampleKeyValueTopDecl() {
fmt.Print(keyValueTopDecl)
// Output: a: "B", b: 2
}
// Person represents a person by name and age.
type Person struct {
Name string
Age int
}
// String returns a string representation of the Person.
func (p Person) String() string {
return fmt.Sprintf("%s: %d", p.Name, p.Age)
}
// ByAge implements sort.Interface for []Person based on
// the Age field.
type ByAge []Person
// Len returns the number of elements in ByAge.
func (a (ByAge)) Len() int { return len(a) }
// Swap swaps the elements in ByAge.
func (a ByAge) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
func (a ByAge) Less(i, j int) bool { return a[i].Age < a[j].Age }
// people is the array of Person
var people = []Person{
{"Bob", 31},
{"John", 42},
{"Michael", 17},
{"Jenny", 26},
}
func ExampleSort() {
fmt.Println(people)
sort.Sort(ByAge(people))
fmt.Println(people)
// Output:
// [Bob: 31 John: 42 Michael: 17 Jenny: 26]
// [Michael: 17 Jenny: 26 Bob: 31 John: 42]
}
`
var exampleTestCases = []struct {
Name, Play, Output string
}{
{
Name: "Hello",
Play: exampleHelloPlay,
Output: "Hello, world!\n",
},
{
Name: "Import",
Play: exampleImportPlay,
},
{
Name: "KeyValue",
Play: exampleKeyValuePlay,
Output: "a: \"A\", b: 1\n",
},
{
Name: "KeyValueImport",
Play: exampleKeyValueImportPlay,
Output: "Name: \"play\"\n",
},
{
Name: "KeyValueTopDecl",
Play: exampleKeyValueTopDeclPlay,
Output: "a: \"B\", b: 2\n",
},
{
Name: "Sort",
Play: exampleSortPlay,
Output: "[Bob: 31 John: 42 Michael: 17 Jenny: 26]\n[Michael: 17 Jenny: 26 Bob: 31 John: 42]\n",
},
}
const exampleHelloPlay = `package main
import (
"fmt"
)
func main() {
fmt.Println("Hello, world!")
}
`
const exampleImportPlay = `package main
import (
"fmt"
"log"
"os/exec"
)
func main() {
out, err := exec.Command("date").Output()
if err != nil {
log.Fatal(err)
}
fmt.Printf("The date is %s\n", out)
}
`
const exampleKeyValuePlay = `package main
import (
"fmt"
)
func main() {
v := struct {
a string
b int
}{
a: "A",
b: 1,
}
fmt.Print(v)
}
`
const exampleKeyValueImportPlay = `package main
import (
"flag"
"fmt"
)
func main() {
f := flag.Flag{
Name: "play",
}
fmt.Print(f)
}
`
const exampleKeyValueTopDeclPlay = `package main
import (
"fmt"
)
var keyValueTopDecl = struct {
a string
b int
}{
a: "B",
b: 2,
}
func main() {
fmt.Print(keyValueTopDecl)
}
`
const exampleSortPlay = `package main
import (
"fmt"
"sort"
)
// Person represents a person by name and age.
type Person struct {
Name string
Age int
}
// String returns a string representation of the Person.
func (p Person) String() string {
return fmt.Sprintf("%s: %d", p.Name, p.Age)
}
// ByAge implements sort.Interface for []Person based on
// the Age field.
type ByAge []Person
// Len returns the number of elements in ByAge.
func (a ByAge) Len() int { return len(a) }
// Swap swaps the elements in ByAge.
func (a ByAge) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
func (a ByAge) Less(i, j int) bool { return a[i].Age < a[j].Age }
// people is the array of Person
var people = []Person{
{"Bob", 31},
{"John", 42},
{"Michael", 17},
{"Jenny", 26},
}
func main() {
fmt.Println(people)
sort.Sort(ByAge(people))
fmt.Println(people)
}
`
func TestExamples(t *testing.T) {
fset := token.NewFileSet()
file, err := parser.ParseFile(fset, "test.go", strings.NewReader(exampleTestFile), parser.ParseComments)
if err != nil {
t.Fatal(err)
}
for i, e := range doc.Examples(file) {
c := exampleTestCases[i]
if e.Name != c.Name {
t.Errorf("got Name == %q, want %q", e.Name, c.Name)
}
if w := c.Play; w != "" {
g := formatFile(t, fset, e.Play)
if g != w {
t.Errorf("%s: got Play == %q, want %q", c.Name, g, w)
}
}
if g, w := e.Output, c.Output; g != w {
t.Errorf("%s: got Output == %q, want %q", c.Name, g, w)
}
}
}
const exampleWholeFile = `package foo_test
type X int
func (X) Foo() {
}
func (X) TestBlah() {
}
func (X) BenchmarkFoo() {
}
func Example() {
fmt.Println("Hello, world!")
// Output: Hello, world!
}
`
const exampleWholeFileOutput = `package main
type X int
func (X) Foo() {
}
func (X) TestBlah() {
}
func (X) BenchmarkFoo() {
}
func main() {
fmt.Println("Hello, world!")
}
`
const exampleWholeFileFunction = `package foo_test
func Foo(x int) {
}
func Example() {
fmt.Println("Hello, world!")
// Output: Hello, world!
}
`
const exampleWholeFileFunctionOutput = `package main
func Foo(x int) {
}
func main() {
fmt.Println("Hello, world!")
}
`
const exampleWholeFileExternalFunction = `package foo_test
func foo(int)
func Example() {
foo(42)
// Output:
}
`
const exampleWholeFileExternalFunctionOutput = `package main
func foo(int)
func main() {
foo(42)
}
`
var exampleWholeFileTestCases = []struct {
Title, Source, Play, Output string
}{
{
"Methods",
exampleWholeFile,
exampleWholeFileOutput,
"Hello, world!\n",
},
{
"Function",
exampleWholeFileFunction,
exampleWholeFileFunctionOutput,
"Hello, world!\n",
},
{
"ExternalFunction",
exampleWholeFileExternalFunction,
exampleWholeFileExternalFunctionOutput,
"",
},
}
func TestExamplesWholeFile(t *testing.T) {
for _, c := range exampleWholeFileTestCases {
fset := token.NewFileSet()
file, err := parser.ParseFile(fset, "test.go", strings.NewReader(c.Source), parser.ParseComments)
if err != nil {
t.Fatal(err)
}
es := doc.Examples(file)
if len(es) != 1 {
t.Fatalf("%s: wrong number of examples; got %d want 1", c.Title, len(es))
}
e := es[0]
if e.Name != "" {
t.Errorf("%s: got Name == %q, want %q", c.Title, e.Name, "")
}
if g, w := formatFile(t, fset, e.Play), c.Play; g != w {
t.Errorf("%s: got Play == %q, want %q", c.Title, g, w)
}
if g, w := e.Output, c.Output; g != w {
t.Errorf("%s: got Output == %q, want %q", c.Title, g, w)
}
}
}
const exampleInspectSignature = `package foo_test
import (
"bytes"
"io"
)
func getReader() io.Reader { return nil }
func do(b bytes.Reader) {}
func Example() {
getReader()
do()
// Output:
}
func ExampleIgnored() {
}
`
const exampleInspectSignatureOutput = `package main
import (
"bytes"
"io"
)
func getReader() io.Reader { return nil }
func do(b bytes.Reader) {}
func main() {
getReader()
do()
}
`
func TestExampleInspectSignature(t *testing.T) {
// Verify that "bytes" and "io" are imported. See issue #28492.
fset := token.NewFileSet()
file, err := parser.ParseFile(fset, "test.go", strings.NewReader(exampleInspectSignature), parser.ParseComments)
if err != nil {
t.Fatal(err)
}
es := doc.Examples(file)
if len(es) != 2 {
t.Fatalf("wrong number of examples; got %d want 2", len(es))
}
// We are interested in the first example only.
e := es[0]
if e.Name != "" {
t.Errorf("got Name == %q, want %q", e.Name, "")
}
if g, w := formatFile(t, fset, e.Play), exampleInspectSignatureOutput; g != w {
t.Errorf("got Play == %q, want %q", g, w)
}
if g, w := e.Output, ""; g != w {
t.Errorf("got Output == %q, want %q", g, w)
}
}
const exampleEmpty = `
package p
func Example() {}
func Example_a()
`
const exampleEmptyOutput = `package main
func main() {}
func main()
`
func TestExampleEmpty(t *testing.T) {
fset := token.NewFileSet()
file, err := parser.ParseFile(fset, "test.go", strings.NewReader(exampleEmpty), parser.ParseComments)
if err != nil {
t.Fatal(err)
}
es := doc.Examples(file)
if len(es) != 1 {
t.Fatalf("wrong number of examples; got %d want 1", len(es))
}
e := es[0]
if e.Name != "" {
t.Errorf("got Name == %q, want %q", e.Name, "")
}
if g, w := formatFile(t, fset, e.Play), exampleEmptyOutput; g != w {
t.Errorf("got Play == %q, want %q", g, w)
}
if g, w := e.Output, ""; g != w {
t.Errorf("got Output == %q, want %q", g, w)
}
}
func formatFile(t *testing.T, fset *token.FileSet, n *ast.File) string {
if n == nil {
return "<nil>"
}
var buf bytes.Buffer
if err := format.Node(&buf, fset, n); err != nil {
t.Fatal(err)
}
return buf.String()
}
// This example illustrates how to use NewFromFiles
// to compute package documentation with examples.
func ExampleNewFromFiles() {
// src and test are two source files that make up
// a package whose documentation will be computed.
const src = `
// This is the package comment.
package p
import "fmt"
// This comment is associated with the Greet function.
func Greet(who string) {
fmt.Printf("Hello, %s!\n", who)
}
`
const test = `
package p_test
// This comment is associated with the ExampleGreet_world example.
func ExampleGreet_world() {
Greet("world")
}
`
// Create the AST by parsing src and test.
fset := token.NewFileSet()
files := []*ast.File{
mustParse(fset, "src.go", src),
mustParse(fset, "src_test.go", test),
}
// Compute package documentation with examples.
p, err := doc.NewFromFiles(fset, files, "example.com/p")
if err != nil {
panic(err)
}
fmt.Printf("package %s - %s", p.Name, p.Doc)
fmt.Printf("func %s - %s", p.Funcs[0].Name, p.Funcs[0].Doc)
fmt.Printf(" ⤷ example with suffix %q - %s", p.Funcs[0].Examples[0].Suffix, p.Funcs[0].Examples[0].Doc)
// Output:
// package p - This is the package comment.
// func Greet - This comment is associated with the Greet function.
// ⤷ example with suffix "world" - This comment is associated with the ExampleGreet_world example.
}
func TestClassifyExamples(t *testing.T) {
const src = `
package p
const Const1 = 0
var Var1 = 0
type (
Type1 int
Type1_Foo int
Type1_foo int
type2 int
Embed struct { Type1 }
Uembed struct { type2 }
)
func Func1() {}
func Func1_Foo() {}
func Func1_foo() {}
func func2() {}
func (Type1) Func1() {}
func (Type1) Func1_Foo() {}
func (Type1) Func1_foo() {}
func (Type1) func2() {}
func (type2) Func1() {}
type (
Conflict int
Conflict_Conflict int
Conflict_conflict int
)
func (Conflict) Conflict() {}
`
const test = `
package p_test
func ExampleConst1() {} // invalid - no support for consts and vars
func ExampleVar1() {} // invalid - no support for consts and vars
func Example() {}
func Example_() {} // invalid - suffix must start with a lower-case letter
func Example_suffix() {}
func Example_suffix_xX_X_x() {}
func Example_世界() {} // invalid - suffix must start with a lower-case letter
func Example_123() {} // invalid - suffix must start with a lower-case letter
func Example_BadSuffix() {} // invalid - suffix must start with a lower-case letter
func ExampleType1() {}
func ExampleType1_() {} // invalid - suffix must start with a lower-case letter
func ExampleType1_suffix() {}
func ExampleType1_BadSuffix() {} // invalid - suffix must start with a lower-case letter
func ExampleType1_Foo() {}
func ExampleType1_Foo_suffix() {}
func ExampleType1_Foo_BadSuffix() {} // invalid - suffix must start with a lower-case letter
func ExampleType1_foo() {}
func ExampleType1_foo_suffix() {}
func ExampleType1_foo_Suffix() {} // matches Type1, instead of Type1_foo
func Exampletype2() {} // invalid - cannot match unexported
func ExampleFunc1() {}
func ExampleFunc1_() {} // invalid - suffix must start with a lower-case letter
func ExampleFunc1_suffix() {}
func ExampleFunc1_BadSuffix() {} // invalid - suffix must start with a lower-case letter
func ExampleFunc1_Foo() {}
func ExampleFunc1_Foo_suffix() {}
func ExampleFunc1_Foo_BadSuffix() {} // invalid - suffix must start with a lower-case letter
func ExampleFunc1_foo() {}
func ExampleFunc1_foo_suffix() {}
func ExampleFunc1_foo_Suffix() {} // matches Func1, instead of Func1_foo
func Examplefunc1() {} // invalid - cannot match unexported
func ExampleType1_Func1() {}
func ExampleType1_Func1_() {} // invalid - suffix must start with a lower-case letter
func ExampleType1_Func1_suffix() {}
func ExampleType1_Func1_BadSuffix() {} // invalid - suffix must start with a lower-case letter
func ExampleType1_Func1_Foo() {}
func ExampleType1_Func1_Foo_suffix() {}
func ExampleType1_Func1_Foo_BadSuffix() {} // invalid - suffix must start with a lower-case letter
func ExampleType1_Func1_foo() {}
func ExampleType1_Func1_foo_suffix() {}
func ExampleType1_Func1_foo_Suffix() {} // matches Type1.Func1, instead of Type1.Func1_foo
func ExampleType1_func2() {} // matches Type1, instead of Type1.func2
func ExampleEmbed_Func1() {} // invalid - no support for forwarded methods from embedding exported type
func ExampleUembed_Func1() {} // methods from embedding unexported types are OK
func ExampleUembed_Func1_suffix() {}
func ExampleConflict_Conflict() {} // ambiguous with either Conflict or Conflict_Conflict type
func ExampleConflict_conflict() {} // ambiguous with either Conflict or Conflict_conflict type
func ExampleConflict_Conflict_suffix() {} // ambiguous with either Conflict or Conflict_Conflict type
func ExampleConflict_conflict_suffix() {} // ambiguous with either Conflict or Conflict_conflict type
`
// Parse literal source code as a *doc.Package.
fset := token.NewFileSet()
files := []*ast.File{
mustParse(fset, "src.go", src),
mustParse(fset, "src_test.go", test),
}
p, err := doc.NewFromFiles(fset, files, "example.com/p")
if err != nil {
t.Fatalf("doc.NewFromFiles: %v", err)
}
// Collect the association of examples to top-level identifiers.
got := map[string][]string{}
got[""] = exampleNames(p.Examples)
for _, f := range p.Funcs {
got[f.Name] = exampleNames(f.Examples)
}
for _, t := range p.Types {
got[t.Name] = exampleNames(t.Examples)
for _, f := range t.Funcs {
got[f.Name] = exampleNames(f.Examples)
}
for _, m := range t.Methods {
got[t.Name+"."+m.Name] = exampleNames(m.Examples)
}
}
want := map[string][]string{
"": {"", "suffix", "suffix_xX_X_x"}, // Package-level examples.
"Type1": {"", "foo_Suffix", "func2", "suffix"},
"Type1_Foo": {"", "suffix"},
"Type1_foo": {"", "suffix"},
"Func1": {"", "foo_Suffix", "suffix"},
"Func1_Foo": {"", "suffix"},
"Func1_foo": {"", "suffix"},
"Type1.Func1": {"", "foo_Suffix", "suffix"},
"Type1.Func1_Foo": {"", "suffix"},
"Type1.Func1_foo": {"", "suffix"},
"Uembed.Func1": {"", "suffix"},
// These are implementation dependent due to the ambiguous parsing.
"Conflict_Conflict": {"", "suffix"},
"Conflict_conflict": {"", "suffix"},
}
for id := range got {
if !reflect.DeepEqual(got[id], want[id]) {
t.Errorf("classification mismatch for %q:\ngot %q\nwant %q", id, got[id], want[id])
}
}
}
func exampleNames(exs []*doc.Example) (out []string) {
for _, ex := range exs {
out = append(out, ex.Suffix)
}
return out
}
func mustParse(fset *token.FileSet, filename, src string) *ast.File {
f, err := parser.ParseFile(fset, filename, src, parser.ParseComments)
if err != nil {
panic(err)
}
return f
}