1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
|
require_relative '../../spec_helper'
describe "Integer#<< (with n << m)" do
context "fixnum" do
it "returns n shifted left m bits when n > 0, m > 0" do
(1 << 1).should == 2
end
it "returns n shifted left m bits when n < 0, m > 0" do
(-1 << 1).should == -2
(-7 << 1).should == -14
(-42 << 2).should == -168
end
it "returns n shifted right m bits when n > 0, m < 0" do
(2 << -1).should == 1
end
it "returns n shifted right m bits when n < 0, m < 0" do
(-2 << -1).should == -1
end
it "returns 0 when n == 0" do
(0 << 1).should == 0
end
it "returns n when n > 0, m == 0" do
(1 << 0).should == 1
end
it "returns n when n < 0, m == 0" do
(-1 << 0).should == -1
end
it "returns 0 when n > 0, m < 0 and n < 2**-m" do
(3 << -2).should == 0
(7 << -3).should == 0
(127 << -7).should == 0
# To make sure the exponent is not truncated
(7 << -32).should == 0
(7 << -64).should == 0
end
it "returns -1 when n < 0, m < 0 and n > -(2**-m)" do
(-3 << -2).should == -1
(-7 << -3).should == -1
(-127 << -7).should == -1
# To make sure the exponent is not truncated
(-7 << -32).should == -1
(-7 << -64).should == -1
end
it "returns 0 when m < 0 and m is a Bignum" do
(3 << -bignum_value).should == 0
end
it "returns an Bignum == fixnum_max * 2 when fixnum_max << 1 and n > 0" do
result = fixnum_max << 1
result.should be_an_instance_of(Bignum)
result.should == fixnum_max * 2
end
it "returns an Bignum == fixnum_min * 2 when fixnum_min << 1 and n < 0" do
result = fixnum_min << 1
result.should be_an_instance_of(Bignum)
result.should == fixnum_min * 2
end
it "calls #to_int to convert the argument to an Integer" do
obj = mock("4")
obj.should_receive(:to_int).and_return(4)
(3 << obj).should == 48
end
it "raises a TypeError when #to_int does not return an Integer" do
obj = mock("a string")
obj.should_receive(:to_int).and_return("asdf")
-> { 3 << obj }.should raise_error(TypeError)
end
it "raises a TypeError when passed nil" do
-> { 3 << nil }.should raise_error(TypeError)
end
it "raises a TypeError when passed a String" do
-> { 3 << "4" }.should raise_error(TypeError)
end
end
context "bignum" do
before :each do
@bignum = bignum_value * 16
end
it "returns n shifted left m bits when n > 0, m > 0" do
(@bignum << 4).should == 2361183241434822606848
end
it "returns n shifted left m bits when n < 0, m > 0" do
(-@bignum << 9).should == -75557863725914323419136
end
it "returns n shifted right m bits when n > 0, m < 0" do
(@bignum << -1).should == 73786976294838206464
end
it "returns n shifted right m bits when n < 0, m < 0" do
(-@bignum << -2).should == -36893488147419103232
end
it "returns n when n > 0, m == 0" do
(@bignum << 0).should == @bignum
end
it "returns n when n < 0, m == 0" do
(-@bignum << 0).should == -@bignum
end
it "returns 0 when m < 0 and m == p where 2**p > n >= 2**(p-1)" do
(@bignum << -68).should == 0
end
it "returns 0 when m < 0 and m is a Bignum" do
(@bignum << -bignum_value).should == 0
end
it "returns a Fixnum == fixnum_max when (fixnum_max * 2) << -1 and n > 0" do
result = (fixnum_max * 2) << -1
result.should be_an_instance_of(Fixnum)
result.should == fixnum_max
end
it "returns a Fixnum == fixnum_min when (fixnum_min * 2) << -1 and n < 0" do
result = (fixnum_min * 2) << -1
result.should be_an_instance_of(Fixnum)
result.should == fixnum_min
end
it "calls #to_int to convert the argument to an Integer" do
obj = mock("4")
obj.should_receive(:to_int).and_return(4)
(@bignum << obj).should == 2361183241434822606848
end
it "raises a TypeError when #to_int does not return an Integer" do
obj = mock("a string")
obj.should_receive(:to_int).and_return("asdf")
-> { @bignum << obj }.should raise_error(TypeError)
end
it "raises a TypeError when passed nil" do
-> { @bignum << nil }.should raise_error(TypeError)
end
it "raises a TypeError when passed a String" do
-> { @bignum << "4" }.should raise_error(TypeError)
end
end
end
|
