testing: in example, empty output not distinguished from missing output

Fixes #4485.

R=golang-dev, rsc, adg
CC=golang-dev
https://golang.org/cl/7071050

diff --git a/src/cmd/go/test.go b/src/cmd/go/test.go
index 5d3f21e5e9a89c5c80033e7d44101c508f23f35e..d2498cafce6fe7a0de36ace89380f4ca0231ba29 100644 (file)
--- a/src/cmd/go/test.go
+++ b/src/cmd/go/test.go
@@ -792,7 +792,7 @@ func (t *testFuncs) load(filename, pkg string, seen *bool) error {
                }
        }
        for _, e := range doc.Examples(f) {
-               if e.Output == "" {
+               if e.Output == "" && !e.EmptyOutput {
                        // Don't run examples with no output.
                        continue
                }

diff --git a/src/pkg/go/doc/example.go b/src/pkg/go/doc/example.go
index c7a0cf8c6d302d5968a740f50080680bcbb9213c..f634e16770a3f63095eb8dc9fb9c18e0ffa8e21e 100644 (file)
--- a/src/pkg/go/doc/example.go
+++ b/src/pkg/go/doc/example.go
@@ -19,12 +19,13 @@ import (
 )
 
 type Example struct {
-       Name     string // name of the item being exemplified
-       Doc      string // example function doc string
-       Code     ast.Node
-       Play     *ast.File // a whole program version of the example
-       Comments []*ast.CommentGroup
-       Output   string // expected output
+       Name        string // name of the item being exemplified
+       Doc         string // example function doc string
+       Code        ast.Node
+       Play        *ast.File // a whole program version of the example
+       Comments    []*ast.CommentGroup
+       Output      string // expected output
+       EmptyOutput bool   // expect empty output
 }
 
 func Examples(files ...*ast.File) []*Example {
@@ -55,13 +56,15 @@ func Examples(files ...*ast.File) []*Example {
                        if f.Doc != nil {
                                doc = f.Doc.Text()
                        }
+                       output, hasOutput := exampleOutput(f.Body, file.Comments)
                        flist = append(flist, &Example{
-                               Name:     name[len("Example"):],
-                               Doc:      doc,
-                               Code:     f.Body,
-                               Play:     playExample(file, f.Body),
-                               Comments: file.Comments,
-                               Output:   exampleOutput(f.Body, file.Comments),
+                               Name:        name[len("Example"):],
+                               Doc:         doc,
+                               Code:        f.Body,
+                               Play:        playExample(file, f.Body),
+                               Comments:    file.Comments,
+                               Output:      output,
+                               EmptyOutput: output == "" && hasOutput,
                        })
                }
                if !hasTests && numDecl > 1 && len(flist) == 1 {
@@ -79,7 +82,8 @@ func Examples(files ...*ast.File) []*Example {
 
 var outputPrefix = regexp.MustCompile(`(?i)^[[:space:]]*output:`)
 
-func exampleOutput(b *ast.BlockStmt, comments []*ast.CommentGroup) string {
+// Extracts the expected output and whether there was a valid output comment
+func exampleOutput(b *ast.BlockStmt, comments []*ast.CommentGroup) (output string, ok bool) {
        if _, last := lastComment(b, comments); last != nil {
                // test that it begins with the correct prefix
                text := last.Text()
@@ -90,10 +94,10 @@ func exampleOutput(b *ast.BlockStmt, comments []*ast.CommentGroup) string {
                        if len(text) > 0 && text[0] == '\n' {
                                text = text[1:]
                        }
-                       return text
+                       return text, true
                }
        }
-       return "" // no suitable comment found
+       return "", false // no suitable comment found
 }
 
 // isTest tells whether name looks like a test, example, or benchmark.