1Test::NoWarnings(3)   User Contributed Perl Documentation  Test::NoWarnings(3)
2
3
4

NAME

6       Test::NoWarnings - Make sure you didn't emit any warnings while testing
7

SYNOPSIS

9       For scripts that have no plan
10
11         use Test::NoWarnings;
12
13       that's it, you don't need to do anything else
14
15       For scripts that look like
16
17         use Test::More tests => x;
18
19       change to
20
21         use Test::More tests => x + 1;
22         use Test::NoWarnings;
23

DESCRIPTION

25       In general, your tests shouldn't produce warnings. This modules causes
26       any warnings to be captured and stored. It automatically adds an extra
27       test that will run when your script ends to check that there were no
28       warnings. If there were any warings, the test will give a "not ok" and
29       diagnostics of where, when and what the warning was, including a stack
30       trace of what was going on when the it occurred.
31
32       If some of your tests are supposed to produce warnings then you should
33       be capturing and checking them with Test::Warn, that way
34       Test::NoWarnings will not see them and so not complain.
35
36       The test is run by an "END" block in Test::NoWarnings. It will not be
37       run when any forked children exit.
38

USAGE

40       Simply by using the module, you automatically get an extra test at the
41       end of your script that checks that no warnings were emitted. So just
42       stick
43
44         use Test::NoWarnings;
45
46       at the top of your script and continue as normal.
47
48       If you want more control you can invoke the test manually at any time
49       with "had_no_warnings".
50
51       The warnings your test has generated so far are stored in an array. You
52       can look inside and clear this whenever you want with "warnings()" and
53       "clear_warnings", however, if you are doing this sort of thing then you
54       probably want to use Test::Warn in combination with Test::NoWarnings.
55
56   use vs require
57       You will almost always want to do
58
59         use Test::NoWarnings
60
61       If you do a "require" rather than a "use", then there will be no
62       automatic test at the end of your script.
63
64   Output
65       If warning is captured during your test then the details will output as
66       part of the diagnostics. You will get:
67
68       o the number and name of the test that was executed just before the
69         warning (if no test had been executed these will be 0 and '')
70
71       o the message passed to "warn",
72
73       o a full dump of the stack when warn was called, courtesy of the "Carp"
74         module
75
76       By default, all warning messages will be emitted in one block at the
77       end of your test script.
78
79   The :early pragma
80       One common complaint from people using Test::NoWarnings is that all of
81       the warnings are emitted in one go at the end. While this is the safest
82       and most correct time to emit these diagnostics, it can make debugging
83       these warnings difficult.
84
85       As of Test::NoWarnings 1.04 you can provide an experimental ":early"
86       pragma when loading the module to force warnings to be thrown via diag
87       at the time that they actually occur.
88
89         use Test::NoWarnings ':early';
90
91       As this will cause the diag to be emitted against the previous test and
92       not the one in which the warning actually occurred it is recommended
93       that the pragma be turned on only for debugging and left off when not
94       needed.
95

FUNCTIONS

97   had_no_warnings
98       This checks that there have been warnings emitted by your test scripts.
99       Usually you will not call this explicitly as it is called automatically
100       when your script finishes.
101
102   clear_warnings
103       This will clear the array of warnings that have been captured. If the
104       array is empty then a call to "had_no_warnings()" will produce a pass
105       result.
106
107   warnings
108       This will return the array of warnings captured so far. Each element of
109       this array is an object containing information about the warning. The
110       following methods are available on these object.
111
112       · $warn->getMessage
113
114         Get the message that would been printed by the warning.
115
116       · $warn->getCarp
117
118         Get a stack trace of what was going on when the warning happened,
119         this stack trace is just a string generated by the Carp module.
120
121       · $warn->getTrace
122
123         Get a stack trace object generated by the Devel::StackTrace module.
124         This will return undef if Devel::StackTrace is not installed.
125
126       · $warn->getTest
127
128         Get the number of the test that executed before the warning was
129         emitted.
130
131       · $warn->getTestName
132
133         Get the name of the test that executed before the warning was
134         emitted.
135

PITFALLS

137       When counting your tests for the plan, don't forget to include the test
138       that runs automatically when your script ends.
139

SUPPORT

141       Bugs should be reported via the CPAN bug tracker at
142
143       <http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Test-NoWarnings>
144
145       For other issues, contact the author.
146

HISTORY

148       This was previously known as Test::Warn::None
149

SEE ALSO

151       Test::Builder, Test::Warn
152

AUTHORS

154       Fergal Daly <fergal@esatclear.ie>
155
156       Adam Kennedy <adamk@cpan.org>
157

159       Copyright 2003 - 2007 Fergal Daly.
160
161       Some parts copyright 2010 - 2011 Adam Kennedy.
162
163       This program is free software and comes with no warranty. It is
164       distributed under the LGPL license
165
166       See the file LGPL included in this distribution or
167       http://www.fsf.org/licenses/licenses.html.
168
169
170
171perl v5.30.1                      2020-01-30               Test::NoWarnings(3)
Impressum