panics: use the new facilities of testing.B instead

Lots of panics go away.
Also fix a name error in html/template.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/5498045

18 files changed, 54 insertions, 73 deletions

diff --git a/src/pkg/bytes/bytes_test.go b/src/pkg/bytes/bytes_test.go
index a2a08c20db..2a1d41b910 100644
--- a/src/pkg/bytes/bytes_test.go
+++ b/src/pkg/bytes/bytes_test.go
@@ -289,8 +289,7 @@ func bmIndexByte(b *testing.B, index func([]byte, byte) int, n int) {
 	for i := 0; i < b.N; i++ {
 		j := index(buf, 'x')
 		if j != n-1 {
-			println("bad index", j)
-			panic("bad index")
+			b.Fatal("bad index", j)
 		}
 	}
 	buf[n-1] = '\x00'
@@ -317,7 +316,7 @@ func bmEqual(b *testing.B, equal func([]byte, []byte) bool, n int) {
 	for i := 0; i < b.N; i++ {
 		eq := equal(buf1, buf2)
 		if !eq {
-			panic("bad equal")
+			b.Fatal("bad equal")
 		}
 	}
 	buf1[n-1] = '\x00'
@@ -339,8 +338,7 @@ func bmIndex(b *testing.B, index func([]byte, []byte) int, n int) {
 	for i := 0; i < b.N; i++ {
 		j := index(buf, buf[n-7:])
 		if j != n-7 {
-			println("bad index", j)
-			panic("bad index")
+			b.Fatal("bad index", j)
 		}
 	}
 	buf[n-1] = '\x00'
@@ -362,8 +360,7 @@ func bmIndexEasy(b *testing.B, index func([]byte, []byte) int, n int) {
 	for i := 0; i < b.N; i++ {
 		j := index(buf, buf[n-7:])
 		if j != n-7 {
-			println("bad index", j)
-			panic("bad index")
+			b.Fatal("bad index", j)
 		}
 	}
 	buf[n-1] = '\x00'
@@ -385,8 +382,7 @@ func bmCount(b *testing.B, count func([]byte, []byte) int, n int) {
 	for i := 0; i < b.N; i++ {
 		j := count(buf, buf[n-7:])
 		if j != 1 {
-			println("bad count", j)
-			panic("bad count")
+			b.Fatal("bad count", j)
 		}
 	}
 	buf[n-1] = '\x00'
@@ -408,8 +404,7 @@ func bmCountEasy(b *testing.B, count func([]byte, []byte) int, n int) {
 	for i := 0; i < b.N; i++ {
 		j := count(buf, buf[n-7:])
 		if j != 1 {
-			println("bad count", j)
-			panic("bad count")
+			b.Fatal("bad count", j)
 		}
 	}
 	buf[n-1] = '\x00'
diff --git a/src/pkg/crypto/aes/aes_test.go b/src/pkg/crypto/aes/aes_test.go
index aa1d0df8e9..e500c666d9 100644
--- a/src/pkg/crypto/aes/aes_test.go
+++ b/src/pkg/crypto/aes/aes_test.go
@@ -356,7 +356,7 @@ func BenchmarkEncrypt(b *testing.B) {
 	tt := encryptTests[0]
 	c, err := NewCipher(tt.key)
 	if err != nil {
-		panic("NewCipher")
+		b.Fatal("NewCipher:", err)
 	}
 	out := make([]byte, len(tt.in))
 	b.StartTimer()
diff --git a/src/pkg/encoding/binary/binary_test.go b/src/pkg/encoding/binary/binary_test.go
index 899505e0a5..3e7057ea22 100644
--- a/src/pkg/encoding/binary/binary_test.go
+++ b/src/pkg/encoding/binary/binary_test.go
@@ -197,7 +197,7 @@ func BenchmarkReadStruct(b *testing.B) {
 	}
 	b.StopTimer()
 	if !reflect.DeepEqual(s, t) {
-		panic("no match")
+		b.Fatal("no match")
 	}
 }
 
@@ -251,6 +251,6 @@ func BenchmarkWriteInts(b *testing.B) {
 	}
 	b.StopTimer()
 	if !bytes.Equal(buf.Bytes(), big[:30]) {
-		panic("first half doesn't match")
+		b.Fatalf("first half doesn't match: %x %x", buf.Bytes(), big[:30])
 	}
 }
diff --git a/src/pkg/encoding/gob/timing_test.go b/src/pkg/encoding/gob/timing_test.go
index 47437a607f..1017eb7f51 100644
--- a/src/pkg/encoding/gob/timing_test.go
+++ b/src/pkg/encoding/gob/timing_test.go
@@ -39,7 +39,7 @@ func benchmarkEndToEnd(r io.Reader, w io.Writer, b *testing.B) {
 func BenchmarkEndToEndPipe(b *testing.B) {
 	r, w, err := os.Pipe()
 	if err != nil {
-		panic("can't get pipe:" + err.Error())
+		b.Fatal("can't get pipe:", err)
 	}
 	benchmarkEndToEnd(r, w, b)
 }
diff --git a/src/pkg/encoding/json/bench_test.go b/src/pkg/encoding/json/bench_test.go
index f0c52011a1..333c1c0ce9 100644
--- a/src/pkg/encoding/json/bench_test.go
+++ b/src/pkg/encoding/json/bench_test.go
@@ -84,7 +84,7 @@ func BenchmarkCodeEncoder(b *testing.B) {
 	enc := NewEncoder(ioutil.Discard)
 	for i := 0; i < b.N; i++ {
 		if err := enc.Encode(&codeStruct); err != nil {
-			panic(err)
+			b.Fatal("Encode:", err)
 		}
 	}
 	b.SetBytes(int64(len(codeJSON)))
@@ -98,7 +98,7 @@ func BenchmarkCodeMarshal(b *testing.B) {
 	}
 	for i := 0; i < b.N; i++ {
 		if _, err := Marshal(&codeStruct); err != nil {
-			panic(err)
+			b.Fatal("Marshal:", err)
 		}
 	}
 	b.SetBytes(int64(len(codeJSON)))
@@ -120,7 +120,7 @@ func BenchmarkCodeDecoder(b *testing.B) {
 		buf.WriteByte('\n')
 		buf.WriteByte('\n')
 		if err := dec.Decode(&r); err != nil {
-			panic(err)
+			b.Fatal("Decode:", err)
 		}
 	}
 	b.SetBytes(int64(len(codeJSON)))
@@ -135,7 +135,7 @@ func BenchmarkCodeUnmarshal(b *testing.B) {
 	for i := 0; i < b.N; i++ {
 		var r codeResponse
 		if err := Unmarshal(codeJSON, &r); err != nil {
-			panic(err)
+			b.Fatal("Unmmarshal:", err)
 		}
 	}
 	b.SetBytes(int64(len(codeJSON)))
@@ -150,7 +150,7 @@ func BenchmarkCodeUnmarshalReuse(b *testing.B) {
 	var r codeResponse
 	for i := 0; i < b.N; i++ {
 		if err := Unmarshal(codeJSON, &r); err != nil {
-			panic(err)
+			b.Fatal("Unmmarshal:", err)
 		}
 	}
 	b.SetBytes(int64(len(codeJSON)))
diff --git a/src/pkg/html/template/error.go b/src/pkg/html/template/error.go
index 9622d7e48e..dcac748967 100644
--- a/src/pkg/html/template/error.go
+++ b/src/pkg/html/template/error.go
@@ -183,11 +183,11 @@ const (
 
 func (e *Error) Error() string {
 	if e.Line != 0 {
-		return fmt.Sprintf("exp/template/html:%s:%d: %s", e.Name, e.Line, e.Description)
+		return fmt.Sprintf("html/template:%s:%d: %s", e.Name, e.Line, e.Description)
 	} else if e.Name != "" {
-		return fmt.Sprintf("exp/template/html:%s: %s", e.Name, e.Description)
+		return fmt.Sprintf("html/template:%s: %s", e.Name, e.Description)
 	}
-	return "exp/template/html: " + e.Description
+	return "html/template: " + e.Description
 }
 
 // errorf creates an error given a format string f and args.
diff --git a/src/pkg/html/template/escape_test.go b/src/pkg/html/template/escape_test.go
index 2d15c71844..7702300ffd 100644
--- a/src/pkg/html/template/escape_test.go
+++ b/src/pkg/html/template/escape_test.go
@@ -944,23 +944,23 @@ func TestErrors(t *testing.T) {
 		},
 		{
 			`<input type=button value=onclick=>`,
-			`exp/template/html:z: "=" in unquoted attr: "onclick="`,
+			`html/template:z: "=" in unquoted attr: "onclick="`,
 		},
 		{
 			`<input type=button value= onclick=>`,
-			`exp/template/html:z: "=" in unquoted attr: "onclick="`,
+			`html/template:z: "=" in unquoted attr: "onclick="`,
 		},
 		{
 			`<input type=button value= 1+1=2>`,
-			`exp/template/html:z: "=" in unquoted attr: "1+1=2"`,
+			`html/template:z: "=" in unquoted attr: "1+1=2"`,
 		},
 		{
 			"<a class=`foo>",
-			"exp/template/html:z: \"`\" in unquoted attr: \"`foo\"",
+			"html/template:z: \"`\" in unquoted attr: \"`foo\"",
 		},
 		{
 			`<a style=font:'Arial'>`,
-			`exp/template/html:z: "'" in unquoted attr: "font:'Arial'"`,
+			`html/template:z: "'" in unquoted attr: "font:'Arial'"`,
 		},
 		{
 			`<a=foo>`,
diff --git a/src/pkg/image/draw/bench_test.go b/src/pkg/image/draw/bench_test.go
index 2be91185af..554a0d3fbc 100644
--- a/src/pkg/image/draw/bench_test.go
+++ b/src/pkg/image/draw/bench_test.go
@@ -51,7 +51,7 @@ func bench(b *testing.B, dcm, scm, mcm color.Model, op Op) {
 		}
 		dst = dst1
 	default:
-		panic("unreachable")
+		b.Fatal("unknown destination color model", dcm)
 	}
 
 	var src image.Image
@@ -116,7 +116,7 @@ func bench(b *testing.B, dcm, scm, mcm color.Model, op Op) {
 			Rect:           image.Rect(0, 0, srcw, srch),
 		}
 	default:
-		panic("unreachable")
+		b.Fatal("unknown source color model", scm)
 	}
 
 	var mask image.Image
@@ -137,7 +137,7 @@ func bench(b *testing.B, dcm, scm, mcm color.Model, op Op) {
 		}
 		mask = mask1
 	default:
-		panic("unreachable")
+		b.Fatal("unknown mask color model", mcm)
 	}
 
 	b.StartTimer()
diff --git a/src/pkg/image/jpeg/writer_test.go b/src/pkg/image/jpeg/writer_test.go
index 28e8732136..e4b56d2884 100644
--- a/src/pkg/image/jpeg/writer_test.go
+++ b/src/pkg/image/jpeg/writer_test.go
@@ -105,7 +105,7 @@ func BenchmarkEncodeRGBOpaque(b *testing.B) {
 		}
 	}
 	if !img.Opaque() {
-		panic("expected image to be opaque")
+		b.Fatal("expected image to be opaque")
 	}
 	b.SetBytes(640 * 480 * 4)
 	b.StartTimer()
diff --git a/src/pkg/image/png/writer_test.go b/src/pkg/image/png/writer_test.go
index 1757e14cad..228ecccfb4 100644
--- a/src/pkg/image/png/writer_test.go
+++ b/src/pkg/image/png/writer_test.go
@@ -125,7 +125,7 @@ func BenchmarkEncodeRGBOpaque(b *testing.B) {
 		}
 	}
 	if !img.Opaque() {
-		panic("expected image to be opaque")
+		b.Fatal("expected image to be opaque")
 	}
 	b.SetBytes(640 * 480 * 4)
 	b.StartTimer()
@@ -138,7 +138,7 @@ func BenchmarkEncodeRGBA(b *testing.B) {
 	b.StopTimer()
 	img := image.NewRGBA(image.Rect(0, 0, 640, 480))
 	if img.Opaque() {
-		panic("expected image to not be opaque")
+		b.Fatal("expected image to not be opaque")
 	}
 	b.SetBytes(640 * 480 * 4)
 	b.StartTimer()
diff --git a/src/pkg/image/tiff/reader_test.go b/src/pkg/image/tiff/reader_test.go
index 1a3d23bbd7..ee5dafd996 100644
--- a/src/pkg/image/tiff/reader_test.go
+++ b/src/pkg/image/tiff/reader_test.go
@@ -113,7 +113,7 @@ func BenchmarkDecode(b *testing.B) {
 	for i := 0; i < b.N; i++ {
 		_, err := Decode(r)
 		if err != nil {
-			panic(err)
+			b.Fatal("Decode:", err)
 		}
 	}
 }
diff --git a/src/pkg/math/big/nat_test.go b/src/pkg/math/big/nat_test.go
index e3c6552d9f..25e39273c0 100644
--- a/src/pkg/math/big/nat_test.go
+++ b/src/pkg/math/big/nat_test.go
@@ -5,7 +5,6 @@
 package big
 
 import (
-	"fmt"
 	"io"
 	"strings"
 	"testing"
@@ -402,7 +401,7 @@ func ScanHelper(b *testing.B, base int, x, y Word) {
 	var s string
 	s = z.string(lowercaseDigits[0:base])
 	if t := toString(z, lowercaseDigits[0:base]); t != s {
-		panic(fmt.Sprintf("scanning: got %s; want %s", s, t))
+		b.Fatalf("scanning: got %s; want %s", s, t)
 	}
 	b.StartTimer()
 
diff --git a/src/pkg/net/http/serve_test.go b/src/pkg/net/http/serve_test.go
index c68e6614b1..24e6b50dab 100644
--- a/src/pkg/net/http/serve_test.go
+++ b/src/pkg/net/http/serve_test.go
@@ -1164,15 +1164,15 @@ func BenchmarkClientServer(b *testing.B) {
 	for i := 0; i < b.N; i++ {
 		res, err := Get(ts.URL)
 		if err != nil {
-			panic("Get: " + err.Error())
+			b.Fatal("Get:", err)
 		}
 		all, err := ioutil.ReadAll(res.Body)
 		if err != nil {
-			panic("ReadAll: " + err.Error())
+			b.Fatal("ReadAll:", err)
 		}
 		body := string(all)
 		if body != "Hello world.\n" {
-			panic("Got body: " + body)
+			b.Fatal("Got body:", body)
 		}
 	}
 
diff --git a/src/pkg/net/rpc/server_test.go b/src/pkg/net/rpc/server_test.go
index a52a86e414..c1845fa507 100644
--- a/src/pkg/net/rpc/server_test.go
+++ b/src/pkg/net/rpc/server_test.go
@@ -516,12 +516,10 @@ func benchmarkEndToEnd(dial func() (*Client, error), b *testing.B) {
 			for atomic.AddInt32(&N, -1) >= 0 {
 				err = client.Call("Arith.Add", args, reply)
 				if err != nil {
-					fmt.Printf("Add: expected no error but got string %q", err.Error())
-					panic("rpc error")
+					b.Fatalf("rpc error: Add: expected no error but got string %q", err.Error())
 				}
 				if reply.C != args.A+args.B {
-					fmt.Printf("Add: expected %d got %d", reply.C, args.A+args.B)
-					panic("rpc error")
+					b.Fatalf("rpc error: Add: expected %d got %d", reply.C, args.A+args.B)
 				}
 			}
 			wg.Done()
@@ -536,8 +534,7 @@ func benchmarkEndToEndAsync(dial func() (*Client, error), b *testing.B) {
 	once.Do(startServer)
 	client, err := dial()
 	if err != nil {
-		fmt.Println("error dialing", err)
-		return
+		b.Fatalf("error dialing:", err)
 	}
 
 	// Asynchronous calls
@@ -561,12 +558,11 @@ func benchmarkEndToEndAsync(dial func() (*Client, error), b *testing.B) {
 		}()
 		go func() {
 			for call := range res {
-				a := call.Args.(*Args).A
-				b := call.Args.(*Args).B
-				c := call.Reply.(*Reply).C
-				if a+b != c {
-					fmt.Printf("Add: expected %d got %d", a+b, c)
-					panic("incorrect reply")
+				A := call.Args.(*Args).A
+				B := call.Args.(*Args).B
+				C := call.Reply.(*Reply).C
+				if A+B != C {
+					b.Fatalf("incorrect reply: Add: expected %d got %d", A+B, C)
 				}
 				<-gate
 				if atomic.AddInt32(&recv, -1) == 0 {
diff --git a/src/pkg/old/regexp/all_test.go b/src/pkg/old/regexp/all_test.go
index 9a04360dd1..180dac4d45 100644
--- a/src/pkg/old/regexp/all_test.go
+++ b/src/pkg/old/regexp/all_test.go
@@ -321,8 +321,7 @@ func BenchmarkLiteral(b *testing.B) {
 	b.StartTimer()
 	for i := 0; i < b.N; i++ {
 		if !re.MatchString(x) {
-			println("no match!")
-			break
+			b.Fatal("no match!")
 		}
 	}
 }
@@ -334,8 +333,7 @@ func BenchmarkNotLiteral(b *testing.B) {
 	b.StartTimer()
 	for i := 0; i < b.N; i++ {
 		if !re.MatchString(x) {
-			println("no match!")
-			break
+			b.Fatal("no match!")
 		}
 	}
 }
@@ -347,8 +345,7 @@ func BenchmarkMatchClass(b *testing.B) {
 	b.StartTimer()
 	for i := 0; i < b.N; i++ {
 		if !re.MatchString(x) {
-			println("no match!")
-			break
+			b.Fatal("no match!")
 		}
 	}
 }
@@ -362,8 +359,7 @@ func BenchmarkMatchClass_InRange(b *testing.B) {
 	b.StartTimer()
 	for i := 0; i < b.N; i++ {
 		if !re.MatchString(x) {
-			println("no match!")
-			break
+			b.Fatal("no match!")
 		}
 	}
 }
diff --git a/src/pkg/regexp/all_test.go b/src/pkg/regexp/all_test.go
index 8810796daf..e729510b51 100644
--- a/src/pkg/regexp/all_test.go
+++ b/src/pkg/regexp/all_test.go
@@ -324,8 +324,7 @@ func BenchmarkLiteral(b *testing.B) {
 	b.StartTimer()
 	for i := 0; i < b.N; i++ {
 		if !re.MatchString(x) {
-			println("no match!")
-			break
+			b.Fatalf("no match!")
 		}
 	}
 }
@@ -337,8 +336,7 @@ func BenchmarkNotLiteral(b *testing.B) {
 	b.StartTimer()
 	for i := 0; i < b.N; i++ {
 		if !re.MatchString(x) {
-			println("no match!")
-			break
+			b.Fatalf("no match!")
 		}
 	}
 }
@@ -350,8 +348,7 @@ func BenchmarkMatchClass(b *testing.B) {
 	b.StartTimer()
 	for i := 0; i < b.N; i++ {
 		if !re.MatchString(x) {
-			println("no match!")
-			break
+			b.Fatalf("no match!")
 		}
 	}
 }
@@ -365,8 +362,7 @@ func BenchmarkMatchClass_InRange(b *testing.B) {
 	b.StartTimer()
 	for i := 0; i < b.N; i++ {
 		if !re.MatchString(x) {
-			println("no match!")
-			break
+			b.Fatalf("no match!")
 		}
 	}
 }
diff --git a/src/pkg/regexp/exec_test.go b/src/pkg/regexp/exec_test.go
index 312bf0275f..e668574a51 100644
--- a/src/pkg/regexp/exec_test.go
+++ b/src/pkg/regexp/exec_test.go
@@ -673,7 +673,7 @@ func benchmark(b *testing.B, re string, n int) {
 	b.SetBytes(int64(n))
 	for i := 0; i < b.N; i++ {
 		if r.Match(t) {
-			panic("match!")
+			b.Fatal("match!")
 		}
 	}
 }
diff --git a/src/pkg/strings/strings_test.go b/src/pkg/strings/strings_test.go
index 8866d220c0..54046d68aa 100644
--- a/src/pkg/strings/strings_test.go
+++ b/src/pkg/strings/strings_test.go
@@ -8,7 +8,6 @@ import (
 	"bytes"
 	"io"
 	"reflect"
-	"strconv"
 	. "strings"
 	"testing"
 	"unicode"
@@ -143,7 +142,7 @@ const benchmarkString = "some_text=some☺value"
 
 func BenchmarkIndexRune(b *testing.B) {
 	if got := IndexRune(benchmarkString, '☺'); got != 14 {
-		panic("wrong index: got=" + strconv.Itoa(got))
+		b.Fatalf("wrong index: expected 14, got=%d", got)
 	}
 	for i := 0; i < b.N; i++ {
 		IndexRune(benchmarkString, '☺')
@@ -152,7 +151,7 @@ func BenchmarkIndexRune(b *testing.B) {
 
 func BenchmarkIndexRuneFastPath(b *testing.B) {
 	if got := IndexRune(benchmarkString, 'v'); got != 17 {
-		panic("wrong index: got=" + strconv.Itoa(got))
+		b.Fatalf("wrong index: expected 17, got=%d", got)
 	}
 	for i := 0; i < b.N; i++ {
 		IndexRune(benchmarkString, 'v')
@@ -161,7 +160,7 @@ func BenchmarkIndexRuneFastPath(b *testing.B) {
 
 func BenchmarkIndex(b *testing.B) {
 	if got := Index(benchmarkString, "v"); got != 17 {
-		panic("wrong index: got=" + strconv.Itoa(got))
+		b.Fatalf("wrong index: expected 17, got=%d", got)
 	}
 	for i := 0; i < b.N; i++ {
 		Index(benchmarkString, "v")