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Source file src/math/big/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  				x := sign + test
   113  				var tx Float
   114  				_, _, err := tx.SetPrec(prec).Parse(x, 0)
   115  				if err != nil {
   116  					t.Errorf("parsing of %s (prec = %d) failed (invalid test case): %v", x, prec, err)
   117  					continue
   118  				}
   119  				b, err := json.Marshal(&tx)
   120  				if err != nil {
   121  					t.Errorf("marshaling of %v (prec = %d) failed: %v", &tx, prec, err)
   122  					continue
   123  				}
   124  				var rx Float
   125  				rx.SetPrec(prec)
   126  				if err := json.Unmarshal(b, &rx); err != nil {
   127  					t.Errorf("unmarshaling of %v (prec = %d) failed: %v", &tx, prec, err)
   128  					continue
   129  				}
   130  				if rx.Cmp(&tx) != 0 {
   131  					t.Errorf("JSON encoding of %v (prec = %d) failed: got %v want %v", &tx, prec, &rx, &tx)
   132  				}
   133  			}
   134  		}
   135  	}
   136  }
   137  

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