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
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
|
<?xml version="1.0" encoding="utf-8" ?>
<!DOCTYPE fileref SYSTEM "fileref.dtd">
<fileref>
<header>
<copyright>
<year>2012</year><year>2018</year>
<holder>Ericsson AB. All Rights Reserved.</holder>
</copyright>
<legalnotice>
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
</legalnotice>
<title>assert.hrl</title>
<prepared></prepared>
<docno></docno>
<date></date>
<rev></rev>
</header>
<file>assert.hrl</file>
<filesummary>Assert macros.</filesummary>
<description>
<p>The include file <c>assert.hrl</c> provides macros for inserting
assertions in your program code.</p>
<p>Include the following directive in the module from which the function is
called:</p>
<code type="none">
-include_lib("stdlib/include/assert.hrl").</code>
<p>When an assertion succeeds, the assert macro yields the atom <c>ok</c>.
When an assertion fails, an exception of type <c>error</c> is generated.
The associated error term has the form <c>{Macro, Info}</c>. <c>Macro</c>
is the macro name, for example, <c>assertEqual</c>. <c>Info</c> is a list
of tagged values, such as <c>[{module, M}, {line, L}, ...]</c>, which
gives more information about the location and cause of the exception. All
entries in the <c>Info</c> list are optional; do not rely programmatically
on any of them being present.</p>
<p>Each assert macro has a corresponding version with an extra argument,
for adding comments to assertions. These can for example be printed as
part of error reports, to clarify the meaning of the check that
failed. For example, <c>?assertEqual(0, fib(0), "Fibonacci is defined
for zero")</c>. The comment text can be any character data (string,
UTF8-binary, or deep list of such data), and will be included in the
error term as <c>{comment, Text}</c>.</p>
<p>If the macro <c>NOASSERT</c> is defined when <c>assert.hrl</c> is read
by the compiler, the macros are defined as equivalent to the atom
<c>ok</c>. The test will not be performed and there is no cost at runtime.</p>
<p>For example, using <c>erlc</c> to compile your modules, the following
disables all assertions:</p>
<code type="none">
erlc -DNOASSERT=true *.erl</code>
<p>(The value of <c>NOASSERT</c> does not matter, only the fact that it is
defined.)</p>
<p>A few other macros also have effect on the enabling or disabling of
assertions:</p>
<list type="bulleted">
<item><p>If <c>NODEBUG</c> is defined, it implies <c>NOASSERT</c> (unless
<c>DEBUG</c> is also defined, which overrides <c>NODEBUG</c>).</p>
</item>
<item><p>If <c>ASSERT</c> is defined, it overrides <c>NOASSERT</c>, that
is, the assertions remain enabled.</p></item>
</list>
<p>If you prefer, you can thus use only <c>DEBUG</c>/<c>NODEBUG</c> as the
main flags to control the behavior of the assertions (which is useful if
you have other compiler conditionals or debugging macros controlled by
those flags), or you can use <c>ASSERT</c>/<c>NOASSERT</c> to control only
the assert macros.</p>
</description>
<section>
<title>Macros</title>
<taglist>
<tag><c>assert(BoolExpr)</c></tag>
<item></item>
<tag><c>assert(BoolExpr, Comment)</c></tag>
<item>
<p>Tests that <c>BoolExpr</c> completes normally returning
<c>true</c>.</p>
</item>
<tag><c>assertNot(BoolExpr)</c></tag>
<item></item>
<tag><c>assertNot(BoolExpr, Comment)</c></tag>
<item>
<p>Tests that <c>BoolExpr</c> completes normally returning
<c>false</c>.</p>
</item>
<tag><c>assertMatch(GuardedPattern, Expr)</c></tag>
<item></item>
<tag><c>assertMatch(GuardedPattern, Expr, Comment)</c></tag>
<item>
<p>Tests that <c>Expr</c> completes normally yielding a value that
matches <c>GuardedPattern</c>, for example:</p>
<code type="none">
?assertMatch({bork, _}, f())</code>
<p>Notice that a guard <c>when ...</c> can be included:</p>
<code type="none">
?assertMatch({bork, X} when X > 0, f())</code>
</item>
<tag><c>assertNotMatch(GuardedPattern, Expr)</c></tag>
<item></item>
<tag><c>assertNotMatch(GuardedPattern, Expr, Comment)</c></tag>
<item>
<p>Tests that <c>Expr</c> completes normally yielding a value that does
not match <c>GuardedPattern</c>.</p>
<p>As in <c>assertMatch</c>, <c>GuardedPattern</c> can have a
<c>when</c> part.</p>
</item>
<tag><c>assertEqual(ExpectedValue, Expr)</c></tag>
<item></item>
<tag><c>assertEqual(ExpectedValue, Expr, Comment)</c></tag>
<item>
<p>Tests that <c>Expr</c> completes normally yielding a value that is
exactly equal to <c>ExpectedValue</c>.</p>
</item>
<tag><c>assertNotEqual(ExpectedValue, Expr)</c></tag>
<item></item>
<tag><c>assertNotEqual(ExpectedValue, Expr, Comment)</c></tag>
<item>
<p>Tests that <c>Expr</c> completes normally yielding a value that is
not exactly equal to <c>ExpectedValue</c>.</p>
</item>
<tag><c>assertException(Class, Term, Expr)</c></tag>
<item></item>
<tag><c>assertException(Class, Term, Expr, Comment)</c></tag>
<item>
<p>Tests that <c>Expr</c> completes abnormally with an exception of type
<c>Class</c> and with the associated <c>Term</c>. The assertion fails
if <c>Expr</c> raises a different exception or if it completes
normally returning any value.</p>
<p>Notice that both <c>Class</c> and <c>Term</c> can be guarded
patterns, as in <c>assertMatch</c>.</p>
</item>
<tag><c>assertNotException(Class, Term, Expr)</c></tag>
<item></item>
<tag><c>assertNotException(Class, Term, Expr, Comment)</c></tag>
<item>
<p>Tests that <c>Expr</c> does not evaluate abnormally with an
exception of type <c>Class</c> and with the associated <c>Term</c>.
The assertion succeeds if <c>Expr</c> raises a different exception or
if it completes normally returning any value.</p>
<p>As in <c>assertException</c>, both <c>Class</c> and <c>Term</c> can
be guarded patterns.</p>
</item>
<tag><c>assertError(Term, Expr)</c></tag>
<item></item>
<tag><c>assertError(Term, Expr, Comment)</c></tag>
<item>
<p>Equivalent to <c>assertException(error, Term, Expr)</c></p>
</item>
<tag><c>assertExit(Term, Expr)</c></tag>
<item></item>
<tag><c>assertExit(Term, Expr, Comment)</c></tag>
<item>
<p>Equivalent to <c>assertException(exit, Term, Expr)</c></p>
</item>
<tag><c>assertThrow(Term, Expr)</c></tag>
<item></item>
<tag><c>assertThrow(Term, Expr, Comment)</c></tag>
<item>
<p>Equivalent to <c>assertException(throw, Term, Expr)</c></p>
</item>
</taglist>
</section>
<section>
<title>See Also</title>
<p><seealso marker="compiler:compile"><c>compile(3)</c></seealso>,
<seealso marker="erts:erlc"><c>erlc(3)</c></seealso></p>
</section>
</fileref>
|
