cmd/godoc: Add a basic regression test.

R=adg, bradfitz
CC=golang-dev
https://golang.org/cl/11419044

cmd/godoc/godoc_test.go

@@ -0,0 +1,70 @@
+// 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 main_test
+
+import (
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"regexp"
+	"testing"
+)
+
+var godocTests = []struct {
+	args    []string
+	matches []string // regular expressions
+}{
+	{
+		[]string{"fmt"},
+		[]string{
+			`import "fmt"`,
+			`Package fmt implements formatted I/O`,
+		},
+	},
+	{
+		[]string{"io", "WriteString"},
+		[]string{
+			`import "io"`,
+			`func WriteString\(`,
+		},
+	},
+}
+
+// Basic regression test for godoc command-line tool.
+func TestGodoc(t *testing.T) {
+	tmp, err := ioutil.TempDir("", "godoc-regtest-")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(tmp)
+
+	bin := filepath.Join(tmp, "godoc")
+	cmd := exec.Command("go", "build", "-o", bin)
+	if err := cmd.Run(); err != nil {
+		t.Fatalf("Building godoc: %v", err)
+	}
+
+	for _, test := range godocTests {
+		cmd := exec.Command(bin, test.args...)
+		cmd.Args[0] = "godoc"
+		out, err := cmd.CombinedOutput()
+		if err != nil {
+			t.Errorf("Running with args %#v: %v", test.args, err)
+			continue
+		}
+		logged := false
+		for _, pat := range test.matches {
+			re := regexp.MustCompile(pat)
+			if !re.Match(out) {
+				if !logged {
+					t.Logf("Output of running with args %#v:\n%s", test.args, out)
+					logged = true
+				}
+				t.Errorf("Did not match /%v/", pat)
+			}
+		}
+	}
+}