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
166
167
168
169
170
171
|
1
00:00:00,320 --> 00:00:04,059
So let's start our lesson on white docs testing by considering again the
2
00:00:04,059 --> 00:00:07,470
program PrintSum. If you remember, this is the same program that we used when
3
00:00:07,470 --> 00:00:10,300
we were talking about black box testing. It's the program that takes two
4
00:00:10,300 --> 00:00:14,050
integers, A and B, and produces, as a result, the sum of the two.
5
00:00:14,050 --> 00:00:16,570
And when we were looking at this problem in the context of black
6
00:00:16,570 --> 00:00:17,760
box testing, we did not look at
7
00:00:17,760 --> 00:00:19,700
implementation. But that's exactly what we're going to
8
00:00:19,700 --> 00:00:22,090
do now. So we're going to open the box and look at how the
9
00:00:22,090 --> 00:00:25,700
code is implemented. And as you can see, the programmer was kind of creative.
10
00:00:25,700 --> 00:00:28,670
Because instead of just adding the two numbers and printing them, he
11
00:00:28,670 --> 00:00:32,080
or she also decided to print them in a specific color depending
12
00:00:32,080 --> 00:00:36,840
on whether they were positive numbers or negative numbers. So positive results
13
00:00:36,840 --> 00:00:40,040
are printed in red and negative results are printed in blue. And as
14
00:00:40,040 --> 00:00:41,970
you can see by looking at the code we can see some
15
00:00:41,970 --> 00:00:45,150
interesting cases that we might want to test. For instance you can
16
00:00:45,150 --> 00:00:48,190
see that there are two decisions made here. So we might decide
17
00:00:48,190 --> 00:00:51,100
that this is an interesting case and therefore we want to test it.
18
00:00:51,100 --> 00:00:53,770
Similarly we might look at this other case and we might
19
00:00:53,770 --> 00:00:56,465
also decide that this is another interesting case and therefore we
20
00:00:56,465 --> 00:00:58,970
want to test this one as well. So let's discuss this
21
00:00:58,970 --> 00:01:01,480
in a slightly more formal way by introducing the concept of
22
00:01:01,480 --> 00:01:05,110
coverage criteria which are really the essence of why box testing.
23
00:01:05,110 --> 00:01:08,930
First of all coverage criteria are defined in terms of test
24
00:01:08,930 --> 00:01:13,460
requirements where test requirements are the elements, the entities in the
25
00:01:13,460 --> 00:01:16,250
code that we need to exercise. That we need to execute
26
00:01:16,250 --> 00:01:18,690
in order to satisfy the criteria. And we'll see plenty
27
00:01:18,690 --> 00:01:21,430
of examples of that. And normally, when I apply a coverage
28
00:01:21,430 --> 00:01:24,810
criterion, my result is a set of test specifications. And we
29
00:01:24,810 --> 00:01:26,540
already saw test specifications. Those
30
00:01:26,540 --> 00:01:29,540
are basically descriptions, specifications, of how
31
00:01:29,540 --> 00:01:32,786
the tests should be in order to satisfy the requirements. And
32
00:01:32,786 --> 00:01:36,210
they also result in actual test cases, which are instantiations of
33
00:01:36,210 --> 00:01:39,470
the test specifications. And again this is exactly analogous to what
34
00:01:39,470 --> 00:01:41,830
we saw when we were talking about the black box testing.
35
00:01:41,830 --> 00:01:43,960
So let's see what this means by going back to our
36
00:01:43,960 --> 00:01:46,680
example. A minute ago, we looked at the print sum code
37
00:01:46,680 --> 00:01:50,000
and we identified two interesting cases for our code. And those
38
00:01:50,000 --> 00:01:53,430
are exactly our test requirements. So we have a first test
39
00:01:53,430 --> 00:01:57,840
requirement here, which is the execution of this particular statement and
40
00:01:57,840 --> 00:02:01,500
a second requirement here and this one corresponds to the execution
41
00:02:01,500 --> 00:02:04,580
of this other statement. So for this example there are two
42
00:02:04,580 --> 00:02:06,920
things that we need to do in order to satisfy our
43
00:02:06,920 --> 00:02:10,100
coverage requirements. Execute this statement and execute this statement.
|
