github.com/q45/go@v0.0.0-20151101211701-a4fb8c13db3f/src/cmd/compile/internal/big/decimal_test.go (about)

     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 "testing"
     8  
     9  func TestDecimalString(t *testing.T) {
    10  	for _, test := range []struct {
    11  		x    decimal
    12  		want string
    13  	}{
    14  		{want: "0"},
    15  		{decimal{nil, 1000}, "0"}, // exponent of 0 is ignored
    16  		{decimal{[]byte("12345"), 0}, "0.12345"},
    17  		{decimal{[]byte("12345"), -3}, "0.00012345"},
    18  		{decimal{[]byte("12345"), +3}, "123.45"},
    19  		{decimal{[]byte("12345"), +10}, "1234500000"},
    20  	} {
    21  		if got := test.x.String(); got != test.want {
    22  			t.Errorf("%v == %s; want %s", test.x, got, test.want)
    23  		}
    24  	}
    25  }
    26  
    27  func TestDecimalInit(t *testing.T) {
    28  	for _, test := range []struct {
    29  		x     Word
    30  		shift int
    31  		want  string
    32  	}{
    33  		{0, 0, "0"},
    34  		{0, -100, "0"},
    35  		{0, 100, "0"},
    36  		{1, 0, "1"},
    37  		{1, 10, "1024"},
    38  		{1, 100, "1267650600228229401496703205376"},
    39  		{1, -100, "0.0000000000000000000000000000007888609052210118054117285652827862296732064351090230047702789306640625"},
    40  		{12345678, 8, "3160493568"},
    41  		{12345678, -8, "48225.3046875"},
    42  		{195312, 9, "99999744"},
    43  		{1953125, 9, "1000000000"},
    44  	} {
    45  		var d decimal
    46  		d.init(nat{test.x}.norm(), test.shift)
    47  		if got := d.String(); got != test.want {
    48  			t.Errorf("%d << %d == %s; want %s", test.x, test.shift, got, test.want)
    49  		}
    50  	}
    51  }
    52  
    53  func TestDecimalRounding(t *testing.T) {
    54  	for _, test := range []struct {
    55  		x              uint64
    56  		n              int
    57  		down, even, up string
    58  	}{
    59  		{0, 0, "0", "0", "0"},
    60  		{0, 1, "0", "0", "0"},
    61  
    62  		{1, 0, "0", "0", "10"},
    63  		{5, 0, "0", "0", "10"},
    64  		{9, 0, "0", "10", "10"},
    65  
    66  		{15, 1, "10", "20", "20"},
    67  		{45, 1, "40", "40", "50"},
    68  		{95, 1, "90", "100", "100"},
    69  
    70  		{12344999, 4, "12340000", "12340000", "12350000"},
    71  		{12345000, 4, "12340000", "12340000", "12350000"},
    72  		{12345001, 4, "12340000", "12350000", "12350000"},
    73  		{23454999, 4, "23450000", "23450000", "23460000"},
    74  		{23455000, 4, "23450000", "23460000", "23460000"},
    75  		{23455001, 4, "23450000", "23460000", "23460000"},
    76  
    77  		{99994999, 4, "99990000", "99990000", "100000000"},
    78  		{99995000, 4, "99990000", "100000000", "100000000"},
    79  		{99999999, 4, "99990000", "100000000", "100000000"},
    80  
    81  		{12994999, 4, "12990000", "12990000", "13000000"},
    82  		{12995000, 4, "12990000", "13000000", "13000000"},
    83  		{12999999, 4, "12990000", "13000000", "13000000"},
    84  	} {
    85  		x := nat(nil).setUint64(test.x)
    86  
    87  		var d decimal
    88  		d.init(x, 0)
    89  		d.roundDown(test.n)
    90  		if got := d.String(); got != test.down {
    91  			t.Errorf("roundDown(%d, %d) = %s; want %s", test.x, test.n, got, test.down)
    92  		}
    93  
    94  		d.init(x, 0)
    95  		d.round(test.n)
    96  		if got := d.String(); got != test.even {
    97  			t.Errorf("round(%d, %d) = %s; want %s", test.x, test.n, got, test.even)
    98  		}
    99  
   100  		d.init(x, 0)
   101  		d.roundUp(test.n)
   102  		if got := d.String(); got != test.up {
   103  			t.Errorf("roundUp(%d, %d) = %s; want %s", test.x, test.n, got, test.up)
   104  		}
   105  	}
   106  }