tests: fix prints
- delete unnecessary newlines
- make sure formatted prints call the formatting routines

R=adg
CC=golang-dev
https://golang.org/cl/2225046
diff --git a/src/pkg/bytes/buffer_test.go b/src/pkg/bytes/buffer_test.go
index bc696f4..53086a4 100644
--- a/src/pkg/bytes/buffer_test.go
+++ b/src/pkg/bytes/buffer_test.go
@@ -30,19 +30,19 @@
 	bytes := buf.Bytes()
 	str := buf.String()
 	if buf.Len() != len(bytes) {
-		t.Errorf("%s: buf.Len() == %d, len(buf.Bytes()) == %d\n", testname, buf.Len(), len(bytes))
+		t.Errorf("%s: buf.Len() == %d, len(buf.Bytes()) == %d", testname, buf.Len(), len(bytes))
 	}
 
 	if buf.Len() != len(str) {
-		t.Errorf("%s: buf.Len() == %d, len(buf.String()) == %d\n", testname, buf.Len(), len(str))
+		t.Errorf("%s: buf.Len() == %d, len(buf.String()) == %d", testname, buf.Len(), len(str))
 	}
 
 	if buf.Len() != len(s) {
-		t.Errorf("%s: buf.Len() == %d, len(s) == %d\n", testname, buf.Len(), len(s))
+		t.Errorf("%s: buf.Len() == %d, len(s) == %d", testname, buf.Len(), len(s))
 	}
 
 	if string(bytes) != s {
-		t.Errorf("%s: string(buf.Bytes()) == %q, s == %q\n", testname, string(bytes), s)
+		t.Errorf("%s: string(buf.Bytes()) == %q, s == %q", testname, string(bytes), s)
 	}
 }
 
@@ -55,10 +55,10 @@
 	for ; n > 0; n-- {
 		m, err := buf.WriteString(fus)
 		if m != len(fus) {
-			t.Errorf(testname+" (fill 2): m == %d, expected %d\n", m, len(fus))
+			t.Errorf(testname+" (fill 2): m == %d, expected %d", m, len(fus))
 		}
 		if err != nil {
-			t.Errorf(testname+" (fill 3): err should always be nil, found err == %s\n", err)
+			t.Errorf(testname+" (fill 3): err should always be nil, found err == %s", err)
 		}
 		s += fus
 		check(t, testname+" (fill 4)", buf, s)
@@ -75,10 +75,10 @@
 	for ; n > 0; n-- {
 		m, err := buf.Write(fub)
 		if m != len(fub) {
-			t.Errorf(testname+" (fill 2): m == %d, expected %d\n", m, len(fub))
+			t.Errorf(testname+" (fill 2): m == %d, expected %d", m, len(fub))
 		}
 		if err != nil {
-			t.Errorf(testname+" (fill 3): err should always be nil, found err == %s\n", err)
+			t.Errorf(testname+" (fill 3): err should always be nil, found err == %s", err)
 		}
 		s += string(fub)
 		check(t, testname+" (fill 4)", buf, s)
@@ -110,7 +110,7 @@
 			break
 		}
 		if err != nil {
-			t.Errorf(testname+" (empty 2): err should always be nil, found err == %s\n", err)
+			t.Errorf(testname+" (empty 2): err should always be nil, found err == %s", err)
 		}
 		s = s[n:]
 		check(t, testname+" (empty 3)", buf, s)
@@ -134,10 +134,10 @@
 
 		n, err := buf.Write(Bytes(data[0:1]))
 		if n != 1 {
-			t.Errorf("wrote 1 byte, but n == %d\n", n)
+			t.Errorf("wrote 1 byte, but n == %d", n)
 		}
 		if err != nil {
-			t.Errorf("err should always be nil, but err == %s\n", err)
+			t.Errorf("err should always be nil, but err == %s", err)
 		}
 		check(t, "TestBasicOperations (4)", &buf, "a")
 
@@ -146,7 +146,7 @@
 
 		n, err = buf.Write(Bytes(data[2:26]))
 		if n != 24 {
-			t.Errorf("wrote 25 bytes, but n == %d\n", n)
+			t.Errorf("wrote 25 bytes, but n == %d", n)
 		}
 		check(t, "TestBasicOperations (6)", &buf, string(data[0:26]))
 
@@ -162,14 +162,14 @@
 		buf.WriteByte(data[1])
 		c, err := buf.ReadByte()
 		if err != nil {
-			t.Errorf("ReadByte unexpected eof\n")
+			t.Error("ReadByte unexpected eof")
 		}
 		if c != data[1] {
-			t.Errorf("ReadByte wrong value c=%v\n", c)
+			t.Error("ReadByte wrong value c=%v", c)
 		}
 		c, err = buf.ReadByte()
 		if err == nil {
-			t.Errorf("ReadByte unexpected not eof\n")
+			t.Error("ReadByte unexpected not eof")
 		}
 	}
 }
@@ -238,7 +238,7 @@
 func TestNil(t *testing.T) {
 	var b *Buffer
 	if b.String() != "<nil>" {
-		t.Error("expcted <nil>; got %q", b.String())
+		t.Errorf("expcted <nil>; got %q", b.String())
 	}
 }