Fix printing of named floating point types.

Try to avoid infinite recursion if String fails due to
printing a bad type.

Add test for String method with named basic types.

R=r
CC=golang-dev
http://codereview.appspot.com/207102

1 files changed, 61 insertions, 0 deletions

diff --git a/src/pkg/fmt/stringer_test.go b/src/pkg/fmt/stringer_test.go
new file mode 100644
index 000000000..369f610b2
--- /dev/null
+++ b/src/pkg/fmt/stringer_test.go
@@ -0,0 +1,61 @@
+// Copyright 2010 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 fmt_test
+
+import (
+	. "fmt"
+	"testing"
+)
+
+type TI int
+type TI8 int8
+type TI16 int16
+type TI32 int32
+type TI64 int64
+type TU uint
+type TU8 uint8
+type TU16 uint16
+type TU32 uint32
+type TU64 uint64
+type TUI uintptr
+type TF float
+type TF32 float32
+type TF64 float64
+type TB bool
+type TS string
+
+func (v TI) String() string   { return Sprintf("I: %d", v) }
+func (v TI8) String() string  { return Sprintf("I8: %d", v) }
+func (v TI16) String() string { return Sprintf("I16: %d", v) }
+func (v TI32) String() string { return Sprintf("I32: %d", v) }
+func (v TI64) String() string { return Sprintf("I64: %d", v) }
+func (v TU) String() string   { return Sprintf("U: %d", v) }
+func (v TU8) String() string  { return Sprintf("U8: %d", v) }
+func (v TU16) String() string { return Sprintf("U16: %d", v) }
+func (v TU32) String() string { return Sprintf("U32: %d", v) }
+func (v TU64) String() string { return Sprintf("U64: %d", v) }
+func (v TUI) String() string  { return Sprintf("UI: %d", v) }
+func (v TF) String() string   { return Sprintf("F: %f", v) }
+func (v TF32) String() string { return Sprintf("F32: %f", v) }
+func (v TF64) String() string { return Sprintf("F64: %f", v) }
+func (v TB) String() string   { return Sprintf("B: %t", v) }
+func (v TS) String() string   { return Sprintf("S: %q", v) }
+
+func check(t *testing.T, got, want string) {
+	if got != want {
+		t.Error(got, "!=", want)
+	}
+}
+
+func TestStringer(t *testing.T) {
+	s := Sprintf("%v %v %v %v %v", TI(0), TI8(1), TI16(2), TI32(3), TI64(4))
+	check(t, s, "I: 0 I8: 1 I16: 2 I32: 3 I64: 4")
+	s = Sprintf("%v %v %v %v %v %v", TU(5), TU8(6), TU16(7), TU32(8), TU64(9), TUI(10))
+	check(t, s, "U: 5 U8: 6 U16: 7 U32: 8 U64: 9 UI: 10")
+	s = Sprintf("%v %v %v", TF(1.0), TF32(2.0), TF64(3.0))
+	check(t, s, "F: 1.000000 F32: 2.000000 F64: 3.000000")
+	s = Sprintf("%v %v", TB(true), TS("x"))
+	check(t, s, "B: true S: \"x\"")
+}