doc/codelab/wiki: tests use available TCP port

R=bradfitz, dsymonds, r2, dangabrad, rsc
CC=golang-dev
https://golang.org/cl/4043043

doc/codelab/wiki/Makefile

@@ -13,9 +13,9 @@ CLEANFILES+=index.html srcextract.bin htmlify.bin
 index.html: srcextract.bin htmlify.bin
 	awk '/^!/{system(substr($$0,2)); next} {print}' "$$@" < wiki.html > index.html
 
-test: final.bin get.bin
+test: get.bin
 	bash ./test.sh
-	rm -f final.6 final.bin get.6 get.bin
+	rm -f get.6 get.bin
 
 %.bin: %.$O
 	$(LD) -o $@ $<

doc/codelab/wiki/get.go

@@ -3,16 +3,30 @@ package main
 import (
 	"http"
 	"flag"
+	"fmt"
 	"io"
 	"log"
+	"net"
 	"os"
 	"strings"
 )
 
-var post = flag.String("post", "", "urlencoded form data to POST")
+var (
+	post = flag.String("post", "", "urlencoded form data to POST")
+	port = flag.Bool("port", false, "find open port and print to stdout")
+)
 
 func main() {
 	flag.Parse()
+	if *port {
+		l, err := net.Listen("tcp", "127.0.0.1:0")
+		if err != nil {
+			log.Exit(err)
+		}
+		defer l.Close()
+		fmt.Print(l.Addr().(*net.TCPAddr).Port)
+		return
+	}
 	url := flag.Arg(0)
 	if url == "" {
 		log.Exit("no url supplied")

doc/codelab/wiki/test.sh

 #!/bin/bash
 
-./final.bin &
-wiki_pid=$!
+wiki_pid=
 
 cleanup() {
 	kill $wiki_pid
-	rm -f test_*.out Test.txt
+	rm -f test_*.out Test.txt final-test.bin final-test.go
 	exit ${1:-1}
 }
 trap cleanup INT
 
+port=$(./get.bin -port)
+sed s/8080/$port/ < final.go > final-test.go
+gomake final-test.bin || cleanup 1
+./final-test.bin &
+wiki_pid=$!
+
 sleep 1
 
-./get.bin http://localhost:8080/edit/Test > test_edit.out
+./get.bin http://127.0.0.1:$port/edit/Test > test_edit.out
 diff -u test_edit.out test_edit.good || cleanup 1
-./get.bin -post=body=some%20content http://localhost:8080/save/Test
+./get.bin -post=body=some%20content http://127.0.0.1:$port/save/Test
 diff -u Test.txt test_Test.txt.good || cleanup 1
-./get.bin http://localhost:8080/view/Test > test_view.out
+./get.bin http://127.0.0.1:$port/view/Test > test_view.out
 diff -u test_view.out test_view.good || cleanup 1
 
 echo "Passed"