math/big: implement Float.Text(Un)Marshaler

Fixes #12256.

Change-Id: Ie4a3337996da5c060b27530b076048ffead85f3b
Reviewed-on: https://go-review.googlesource.com/15040
Reviewed-by: Alan Donovan <adonovan@google.com>

1 files changed, 54 insertions, 0 deletions

diff --git a/src/math/big/floatmarsh_test.go b/src/math/big/floatmarsh_test.go
new file mode 100644
index 0000000000..d7ef2fca68
--- /dev/null
+++ b/src/math/big/floatmarsh_test.go
@@ -0,0 +1,54 @@
+// Copyright 2015 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 big
+
+import (
+	"encoding/json"
+	"testing"
+)
+
+var floatVals = []string{
+	"0",
+	"1",
+	"0.1",
+	"2.71828",
+	"1234567890",
+	"3.14e1234",
+	"3.14e-1234",
+	"0.738957395793475734757349579759957975985497e100",
+	"0.73895739579347546656564656573475734957975995797598589749859834759476745986795497e100",
+	"inf",
+	"Inf",
+}
+
+func TestFloatJSONEncoding(t *testing.T) {
+	for _, test := range floatVals {
+		for _, sign := range []string{"", "+", "-"} {
+			for _, prec := range []uint{0, 1, 2, 10, 53, 64, 100, 1000} {
+				x := sign + test
+				var tx Float
+				_, _, err := tx.SetPrec(prec).Parse(x, 0)
+				if err != nil {
+					t.Errorf("parsing of %s (prec = %d) failed (invalid test case): %v", x, prec, err)
+					continue
+				}
+				b, err := json.Marshal(&tx)
+				if err != nil {
+					t.Errorf("marshaling of %v (prec = %d) failed: %v", &tx, prec, err)
+					continue
+				}
+				var rx Float
+				rx.SetPrec(prec)
+				if err := json.Unmarshal(b, &rx); err != nil {
+					t.Errorf("unmarshaling of %v (prec = %d) failed: %v", &tx, prec, err)
+					continue
+				}
+				if rx.Cmp(&tx) != 0 {
+					t.Errorf("JSON encoding of %v (prec = %d) failed: got %v want %v", &tx, prec, &rx, &tx)
+				}
+			}
+		}
+	}
+}