floatmarsh_test.go

Documentation: math/big

		 1  // Copyright 2015 The Go Authors. All rights reserved.
		 2  // Use of this source code is governed by a BSD-style
		 3  // license that can be found in the LICENSE file.
		 4  
		 5  package big
		 6  
		 7  import (
		 8  	"bytes"
		 9  	"encoding/gob"
		10  	"encoding/json"
		11  	"io"
		12  	"testing"
		13  )
		14  
		15  var floatVals = []string{
		16  	"0",
		17  	"1",
		18  	"0.1",
		19  	"2.71828",
		20  	"1234567890",
		21  	"3.14e1234",
		22  	"3.14e-1234",
		23  	"0.738957395793475734757349579759957975985497e100",
		24  	"0.73895739579347546656564656573475734957975995797598589749859834759476745986795497e100",
		25  	"inf",
		26  	"Inf",
		27  }
		28  
		29  func TestFloatGobEncoding(t *testing.T) {
		30  	var medium bytes.Buffer
		31  	enc := gob.NewEncoder(&medium)
		32  	dec := gob.NewDecoder(&medium)
		33  	for _, test := range floatVals {
		34  		for _, sign := range []string{"", "+", "-"} {
		35  			for _, prec := range []uint{0, 1, 2, 10, 53, 64, 100, 1000} {
		36  				for _, mode := range []RoundingMode{ToNearestEven, ToNearestAway, ToZero, AwayFromZero, ToNegativeInf, ToPositiveInf} {
		37  					medium.Reset() // empty buffer for each test case (in case of failures)
		38  					x := sign + test
		39  
		40  					var tx Float
		41  					_, _, err := tx.SetPrec(prec).SetMode(mode).Parse(x, 0)
		42  					if err != nil {
		43  						t.Errorf("parsing of %s (%dbits, %v) failed (invalid test case): %v", x, prec, mode, err)
		44  						continue
		45  					}
		46  
		47  					// If tx was set to prec == 0, tx.Parse(x, 0) assumes precision 64. Correct it.
		48  					if prec == 0 {
		49  						tx.SetPrec(0)
		50  					}
		51  
		52  					if err := enc.Encode(&tx); err != nil {
		53  						t.Errorf("encoding of %v (%dbits, %v) failed: %v", &tx, prec, mode, err)
		54  						continue
		55  					}
		56  
		57  					var rx Float
		58  					if err := dec.Decode(&rx); err != nil {
		59  						t.Errorf("decoding of %v (%dbits, %v) failed: %v", &tx, prec, mode, err)
		60  						continue
		61  					}
		62  
		63  					if rx.Cmp(&tx) != 0 {
		64  						t.Errorf("transmission of %s failed: got %s want %s", x, rx.String(), tx.String())
		65  						continue
		66  					}
		67  
		68  					if rx.Prec() != prec {
		69  						t.Errorf("transmission of %s's prec failed: got %d want %d", x, rx.Prec(), prec)
		70  					}
		71  
		72  					if rx.Mode() != mode {
		73  						t.Errorf("transmission of %s's mode failed: got %s want %s", x, rx.Mode(), mode)
		74  					}
		75  
		76  					if rx.Acc() != tx.Acc() {
		77  						t.Errorf("transmission of %s's accuracy failed: got %s want %s", x, rx.Acc(), tx.Acc())
		78  					}
		79  				}
		80  			}
		81  		}
		82  	}
		83  }
		84  
		85  func TestFloatCorruptGob(t *testing.T) {
		86  	var buf bytes.Buffer
		87  	tx := NewFloat(4 / 3).SetPrec(1000).SetMode(ToPositiveInf)
		88  	if err := gob.NewEncoder(&buf).Encode(tx); err != nil {
		89  		t.Fatal(err)
		90  	}
		91  	b := buf.Bytes()
		92  
		93  	var rx Float
		94  	if err := gob.NewDecoder(bytes.NewReader(b)).Decode(&rx); err != nil {
		95  		t.Fatal(err)
		96  	}
		97  
		98  	if err := gob.NewDecoder(bytes.NewReader(b[:10])).Decode(&rx); err != io.ErrUnexpectedEOF {
		99  		t.Errorf("got %v want EOF", err)
	 100  	}
	 101  
	 102  	b[1] = 0
	 103  	if err := gob.NewDecoder(bytes.NewReader(b)).Decode(&rx); err == nil {
	 104  		t.Fatal("got nil want version error")
	 105  	}
	 106  }
	 107  
	 108  func TestFloatJSONEncoding(t *testing.T) {
	 109  	for _, test := range floatVals {
	 110  		for _, sign := range []string{"", "+", "-"} {
	 111  			for _, prec := range []uint{0, 1, 2, 10, 53, 64, 100, 1000} {
	 112  				if prec > 53 && testing.Short() {
	 113  					continue
	 114  				}
	 115  				x := sign + test
	 116  				var tx Float
	 117  				_, _, err := tx.SetPrec(prec).Parse(x, 0)
	 118  				if err != nil {
	 119  					t.Errorf("parsing of %s (prec = %d) failed (invalid test case): %v", x, prec, err)
	 120  					continue
	 121  				}
	 122  				b, err := json.Marshal(&tx)
	 123  				if err != nil {
	 124  					t.Errorf("marshaling of %v (prec = %d) failed: %v", &tx, prec, err)
	 125  					continue
	 126  				}
	 127  				var rx Float
	 128  				rx.SetPrec(prec)
	 129  				if err := json.Unmarshal(b, &rx); err != nil {
	 130  					t.Errorf("unmarshaling of %v (prec = %d) failed: %v", &tx, prec, err)
	 131  					continue
	 132  				}
	 133  				if rx.Cmp(&tx) != 0 {
	 134  					t.Errorf("JSON encoding of %v (prec = %d) failed: got %v want %v", &tx, prec, &rx, &tx)
	 135  				}
	 136  			}
	 137  		}
	 138  	}
	 139  }
	 140  
	 141  func TestFloatGobDecodeShortBuffer(t *testing.T) {
	 142  	for _, tc := range [][]byte{
	 143  		[]byte{0x1, 0x0, 0x0, 0x0},
	 144  		[]byte{0x1, 0xfa, 0x0, 0x0, 0x0, 0x0},
	 145  	} {
	 146  		err := NewFloat(0).GobDecode(tc)
	 147  		if err == nil {
	 148  			t.Error("expected GobDecode to return error for malformed input")
	 149  		}
	 150  	}
	 151  }
	 152
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