1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Exception correctness</title> 5<link rel="stylesheet" href="../../boostbook.css" type="text/css"> 6<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 7<link rel="home" href="../../index.html" title="Boost.Test"> 8<link rel="up" href="../testing_tools.html" title="Writing unit tests"> 9<link rel="prev" href="extended_comparison/bitwise.html" title="Bitwise comparison"> 10<link rel="next" href="timeout.html" title="Time-out for test cases"> 11</head> 12<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 13<table cellpadding="2" width="100%"><tr> 14<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../../boost.png"></td> 15<td align="center"><a href="../../../../../../index.html">Home</a></td> 16<td align="center"><a href="../../../../../../libs/libraries.htm">Libraries</a></td> 17<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> 18<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> 19<td align="center"><a href="../../../../../../more/index.htm">More</a></td> 20</tr></table> 21<hr> 22<div class="spirit-nav"> 23<a accesskey="p" href="extended_comparison/bitwise.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../testing_tools.html"><img src="../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="timeout.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="section"> 26<div class="titlepage"><div><div><h3 class="title"> 27<a name="boost_test.testing_tools.exception_correctness"></a><a class="link" href="exception_correctness.html" title="Exception correctness">Exception 28 correctness</a> 29</h3></div></div></div> 30<p> 31 Any unexpected/uncaught exception raised in the test case body will be intercepted 32 by the Boost.test framework and will result in the termination of the test-case 33 with the status <code class="computeroutput"><span class="identifier">failed</span></code>. 34 </p> 35<h6> 36<a name="boost_test.testing_tools.exception_correctness.h0"></a> 37 <span class="phrase"><a name="boost_test.testing_tools.exception_correctness.example_descr"></a></span><a class="link" href="exception_correctness.html#boost_test.testing_tools.exception_correctness.example_descr">Example: 38 Uncaught exception</a> 39 </h6> 40<div class="informaltable"><table class="table"> 41<colgroup><col></colgroup> 42<thead><tr><th> 43 <p> 44 Code 45 </p> 46 </th></tr></thead> 47<tbody><tr><td> 48<pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="preprocessor">#define</span> <span class="identifier">BOOST_TEST_MODULE</span> <span class="identifier">example</span> 49<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">test</span><span class="special">/</span><span class="identifier">included</span><span class="special">/</span><span class="identifier">unit_test</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 50 51<span class="keyword">struct</span> <span class="identifier">my_struct</span> <span class="special">{</span> 52 <span class="identifier">my_struct</span><span class="special">(</span><span class="keyword">int</span> <span class="identifier">var_</span><span class="special">)</span> <span class="special">:</span> <span class="identifier">var</span><span class="special">(</span><span class="identifier">var_</span><span class="special">)</span> 53 <span class="special">{</span> 54 <span class="keyword">if</span><span class="special">(</span><span class="identifier">var_</span> <span class="special"><</span> <span class="number">0</span><span class="special">)</span> <span class="keyword">throw</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">runtime_error</span><span class="special">(</span><span class="string">"negative value not allowed"</span><span class="special">);</span> 55 <span class="special">}</span> 56 <span class="keyword">int</span> <span class="identifier">var</span><span class="special">;</span> 57<span class="special">};</span> 58 59<span class="identifier">BOOST_AUTO_TEST_CASE</span><span class="special">(</span> <span class="identifier">test</span> <span class="special">)</span> 60<span class="special">{</span> 61 <span class="identifier">my_struct</span> <span class="identifier">instance</span><span class="special">(-</span><span class="number">2</span><span class="special">);</span> 62 <span class="comment">// ...</span> 63<span class="special">}</span> 64 65<span class="identifier">BOOST_AUTO_TEST_CASE</span><span class="special">(</span> <span class="identifier">test2</span> <span class="special">)</span> 66<span class="special">{</span> 67 <span class="identifier">BOOST_TEST</span><span class="special">(</span><span class="keyword">true</span><span class="special">);</span> 68<span class="special">}</span> 69</pre> 70 </td></tr></tbody> 71</table></div> 72<div class="informaltable"><table class="table"> 73<colgroup><col></colgroup> 74<thead><tr><th> 75 <p> 76 Output 77 </p> 78 </th></tr></thead> 79<tbody><tr><td> 80<pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="special">></span> <span class="identifier">example</span> <span class="special">--</span><span class="identifier">log_level</span><span class="special">=</span><span class="identifier">all</span> 81<span class="identifier">Running</span> <span class="number">2</span> <span class="identifier">test</span> <span class="identifier">cases</span><span class="special">...</span> 82<span class="identifier">Entering</span> <span class="identifier">test</span> <span class="identifier">module</span> <span class="string">"example"</span> 83<span class="identifier">test</span><span class="special">.</span><span class="identifier">cpp</span><span class="special">:</span><span class="number">20</span><span class="special">:</span> <span class="identifier">Entering</span> <span class="identifier">test</span> <span class="keyword">case</span> <span class="string">"test"</span> 84<span class="identifier">unknown</span> <span class="identifier">location</span><span class="special">:</span><span class="number">0</span><span class="special">:</span> <span class="identifier">fatal</span> <span class="identifier">error</span><span class="special">:</span> <span class="identifier">in</span> <span class="string">"test"</span><span class="special">:</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">runtime_error</span><span class="special">:</span> <span class="identifier">negative</span> <span class="identifier">value</span> <span class="keyword">not</span> <span class="identifier">allowed</span> 85<span class="identifier">test</span><span class="special">.</span><span class="identifier">cpp</span><span class="special">:</span><span class="number">20</span><span class="special">:</span> <span class="identifier">last</span> <span class="identifier">checkpoint</span><span class="special">:</span> <span class="string">"test"</span> <span class="identifier">entry</span><span class="special">.</span> 86<span class="identifier">test</span><span class="special">.</span><span class="identifier">cpp</span><span class="special">:</span><span class="number">20</span><span class="special">:</span> <span class="identifier">Leaving</span> <span class="identifier">test</span> <span class="keyword">case</span> <span class="string">"test"</span><span class="special">;</span> <span class="identifier">testing</span> <span class="identifier">time</span><span class="special">:</span> <span class="number">247u</span><span class="identifier">s</span> 87<span class="identifier">test</span><span class="special">.</span><span class="identifier">cpp</span><span class="special">:</span><span class="number">26</span><span class="special">:</span> <span class="identifier">Entering</span> <span class="identifier">test</span> <span class="keyword">case</span> <span class="string">"test2"</span> 88<span class="identifier">test</span><span class="special">.</span><span class="identifier">cpp</span><span class="special">:</span><span class="number">28</span><span class="special">:</span> <span class="identifier">info</span><span class="special">:</span> <span class="identifier">check</span> <span class="keyword">true</span> <span class="identifier">has</span> <span class="identifier">passed</span> 89<span class="identifier">test</span><span class="special">.</span><span class="identifier">cpp</span><span class="special">:</span><span class="number">26</span><span class="special">:</span> <span class="identifier">Leaving</span> <span class="identifier">test</span> <span class="keyword">case</span> <span class="string">"test2"</span><span class="special">;</span> <span class="identifier">testing</span> <span class="identifier">time</span><span class="special">:</span> <span class="number">103u</span><span class="identifier">s</span> 90<span class="identifier">Leaving</span> <span class="identifier">test</span> <span class="identifier">module</span> <span class="string">"example"</span><span class="special">;</span> <span class="identifier">testing</span> <span class="identifier">time</span><span class="special">:</span> <span class="number">492u</span><span class="identifier">s</span> 91 92<span class="special">***</span> <span class="number">1</span> <span class="identifier">failure</span> <span class="identifier">is</span> <span class="identifier">detected</span> <span class="identifier">in</span> <span class="identifier">the</span> <span class="identifier">test</span> <span class="identifier">module</span> <span class="string">"example"</span> 93</pre> 94 </td></tr></tbody> 95</table></div> 96<p> 97 More control over the exception correctness is often required, for instance 98 to test that an expression is raising a specific exception, intentionally. 99 </p> 100<p> 101 The <span class="emphasis"><em>Unit Test Framework</em></span> provides several assertions 102 for testing a code with respect to the exceptions correctness. The following 103 assertions are available: 104 </p> 105<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 106<li class="listitem"> 107 <a class="link" href="../utf_reference/testing_tool_ref/assertion_boost_level_no_throw.html" title="BOOST_<level>_NO_THROW"><code class="computeroutput"><span class="identifier">BOOST_</span><span class="special"><</span><span class="identifier">level</span><span class="special">></span><span class="identifier">_NO_THROW</span></code></a> checks that no exception 108 is raised from an expression, 109 </li> 110<li class="listitem"> 111 <a class="link" href="../utf_reference/testing_tool_ref/assertion_boost_level_throw.html" title="BOOST_<level>_THROW"><code class="computeroutput"><span class="identifier">BOOST_</span><span class="special"><</span><span class="identifier">level</span><span class="special">></span><span class="identifier">_THROW</span></code></a> checks that an expression 112 raises an exception of a specific type 113 </li> 114<li class="listitem"> 115 <a class="link" href="../utf_reference/testing_tool_ref/assertion_boost_level_exception.html" title="BOOST_<level>_EXCEPTION"><code class="computeroutput"><span class="identifier">BOOST_</span><span class="special"><</span><span class="identifier">level</span><span class="special">></span><span class="identifier">_EXCEPTION</span></code></a> checks that an expression 116 raises an exception of a specific type, a passes the exception instance 117 to a predicate function for further validation (introspection for instance) 118 </li> 119</ul></div> 120<p> 121 The following example demonstrate how to use these tools to test the correct 122 behavior of the API of <code class="computeroutput"><span class="identifier">FileWordHistogram</span></code>, 123 in the constructor and the preconditions of the member function. 124 </p> 125<h6> 126<a name="boost_test.testing_tools.exception_correctness.h1"></a> 127 <span class="phrase"><a name="boost_test.testing_tools.exception_correctness.example_descr0"></a></span><a class="link" href="exception_correctness.html#boost_test.testing_tools.exception_correctness.example_descr0">Example: 128 Exception correctness of an API</a> 129 </h6> 130<div class="informaltable"><table class="table"> 131<colgroup><col></colgroup> 132<thead><tr><th> 133 <p> 134 Code 135 </p> 136 </th></tr></thead> 137<tbody><tr><td> 138<pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="preprocessor">#define</span> <span class="identifier">BOOST_TEST_MODULE</span> <span class="identifier">example</span> 139<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">test</span><span class="special">/</span><span class="identifier">included</span><span class="special">/</span><span class="identifier">unit_test</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 140<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">stdexcept</span><span class="special">></span> 141<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">fstream</span><span class="special">></span> 142 143<span class="comment">//! Computes the histogram of the words in a text file</span> 144<span class="keyword">class</span> <span class="identifier">FileWordHistogram</span> 145<span class="special">{</span> 146<span class="keyword">public</span><span class="special">:</span> 147 <span class="comment">//!@throw std::exception if the file does not exist</span> 148 <span class="identifier">FileWordHistogram</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="identifier">filename</span><span class="special">)</span> <span class="special">:</span> <span class="identifier">is_processed</span><span class="special">(</span><span class="keyword">false</span><span class="special">),</span> <span class="identifier">fileStream_</span><span class="special">(</span><span class="identifier">filename</span><span class="special">)</span> <span class="special">{</span> 149 <span class="keyword">if</span><span class="special">(!</span><span class="identifier">fileStream_</span><span class="special">.</span><span class="identifier">is_open</span><span class="special">())</span> <span class="keyword">throw</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">runtime_error</span><span class="special">(</span><span class="string">"Cannot open the file"</span><span class="special">);</span> 150 <span class="special">}</span> 151 152 <span class="comment">//! @returns true on success, false otherwise</span> 153 <span class="keyword">bool</span> <span class="identifier">process</span><span class="special">()</span> <span class="special">{</span> 154 <span class="keyword">if</span><span class="special">(</span><span class="identifier">is_processed</span><span class="special">)</span> <span class="keyword">return</span> <span class="keyword">true</span><span class="special">;</span> 155 156 <span class="comment">// ...</span> 157 <span class="identifier">is_processed</span> <span class="special">=</span> <span class="keyword">true</span><span class="special">;</span> 158 <span class="keyword">return</span> <span class="keyword">true</span><span class="special">;</span> 159 <span class="special">}</span> 160 161 <span class="comment">//!@pre process has been called with status success</span> 162 <span class="comment">//!@throw std::logic_error if preconditions not met</span> 163 <span class="identifier">std</span><span class="special">::</span><span class="identifier">map</span><span class="special"><</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span><span class="special">></span> 164 <span class="identifier">result</span><span class="special">()</span> <span class="keyword">const</span> <span class="special">{</span> 165 <span class="keyword">if</span><span class="special">(!</span><span class="identifier">is_processed</span><span class="special">)</span> 166 <span class="keyword">throw</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">runtime_error</span><span class="special">(</span><span class="string">"\"process\" has not been called or was not successful"</span><span class="special">);</span> 167 <span class="keyword">return</span> <span class="identifier">histogram</span><span class="special">;</span> 168 <span class="special">}</span> 169 170<span class="keyword">private</span><span class="special">:</span> 171 <span class="keyword">bool</span> <span class="identifier">is_processed</span><span class="special">;</span> 172 <span class="identifier">std</span><span class="special">::</span><span class="identifier">ifstream</span> <span class="identifier">fileStream_</span><span class="special">;</span> 173 <span class="identifier">std</span><span class="special">::</span><span class="identifier">map</span><span class="special"><</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span><span class="special">></span> <span class="identifier">histogram</span><span class="special">;</span> 174<span class="special">};</span> 175 176<span class="identifier">BOOST_AUTO_TEST_CASE</span><span class="special">(</span> <span class="identifier">test_throw_behaviour</span> <span class="special">)</span> 177<span class="special">{</span> 178 <span class="comment">// __FILE__ is accessible, no exception expected</span> 179 <span class="identifier">BOOST_REQUIRE_NO_THROW</span><span class="special">(</span> <span class="identifier">FileWordHistogram</span><span class="special">(</span><span class="identifier">__FILE__</span><span class="special">)</span> <span class="special">);</span> 180 181 <span class="comment">// ".. __FILE__" does not exist, API says std::exception, and implementation</span> 182 <span class="comment">// raises std::runtime_error child of std::exception</span> 183 <span class="identifier">BOOST_CHECK_THROW</span><span class="special">(</span> <span class="identifier">FileWordHistogram</span><span class="special">(</span><span class="string">".."</span> <span class="identifier">__FILE__</span><span class="special">),</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">exception</span> <span class="special">);</span> 184 185 <span class="special">{</span> 186 <span class="identifier">FileWordHistogram</span> <span class="identifier">instance</span><span class="special">(</span><span class="identifier">__FILE__</span><span class="special">);</span> 187 188 <span class="comment">// api says "std::logic_error", implementation is wrong.</span> 189 <span class="comment">// std::runtime_error not a child of std::logic_error, not intercepted</span> 190 <span class="comment">// here.</span> 191 <span class="identifier">BOOST_CHECK_THROW</span><span class="special">(</span><span class="identifier">instance</span><span class="special">.</span><span class="identifier">result</span><span class="special">(),</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">logic_error</span><span class="special">);</span> 192 <span class="special">}</span> 193<span class="special">}</span> 194</pre> 195 </td></tr></tbody> 196</table></div> 197<div class="informaltable"><table class="table"> 198<colgroup><col></colgroup> 199<thead><tr><th> 200 <p> 201 Output 202 </p> 203 </th></tr></thead> 204<tbody><tr><td> 205<pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="special">></span> <span class="identifier">example</span> <span class="special">--</span><span class="identifier">log_level</span><span class="special">=</span><span class="identifier">all</span> 206<span class="identifier">Running</span> <span class="number">1</span> <span class="identifier">test</span> <span class="keyword">case</span><span class="special">...</span> 207<span class="identifier">Entering</span> <span class="identifier">test</span> <span class="identifier">module</span> <span class="string">"example"</span> 208<span class="identifier">test</span><span class="special">.</span><span class="identifier">cpp</span><span class="special">:</span><span class="number">47</span><span class="special">:</span> <span class="identifier">Entering</span> <span class="identifier">test</span> <span class="keyword">case</span> <span class="string">"test_throw_behaviour"</span> 209<span class="identifier">test</span><span class="special">.</span><span class="identifier">cpp</span><span class="special">:</span><span class="number">50</span><span class="special">:</span> <span class="identifier">info</span><span class="special">:</span> <span class="identifier">check</span> <span class="char">'no exceptions thrown by FileWordHistogram("test")'</span> <span class="identifier">has</span> <span class="identifier">passed</span> 210<span class="identifier">test</span><span class="special">.</span><span class="identifier">cpp</span><span class="special">:</span><span class="number">54</span><span class="special">:</span> <span class="identifier">info</span><span class="special">:</span> <span class="identifier">check</span> <span class="char">'exception std::exception is caught'</span> <span class="identifier">has</span> <span class="identifier">passed</span> 211<span class="identifier">unknown</span> <span class="identifier">location</span><span class="special">:</span><span class="number">0</span><span class="special">:</span> <span class="identifier">fatal</span> <span class="identifier">error</span><span class="special">:</span> <span class="identifier">in</span> <span class="string">"test_throw_behaviour"</span><span class="special">:</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">runtime_error</span><span class="special">:</span> <span class="string">"process"</span> <span class="identifier">has</span> <span class="keyword">not</span> <span class="identifier">been</span> <span class="identifier">called</span> <span class="keyword">or</span> <span class="identifier">was</span> <span class="keyword">not</span> <span class="identifier">successful</span> 212<span class="identifier">test</span><span class="special">.</span><span class="identifier">cpp</span><span class="special">:</span><span class="number">62</span><span class="special">:</span> <span class="identifier">last</span> <span class="identifier">checkpoint</span> 213<span class="identifier">test</span><span class="special">.</span><span class="identifier">cpp</span><span class="special">:</span><span class="number">47</span><span class="special">:</span> <span class="identifier">Leaving</span> <span class="identifier">test</span> <span class="keyword">case</span> <span class="string">"test_throw_behaviour"</span><span class="special">;</span> <span class="identifier">testing</span> <span class="identifier">time</span><span class="special">:</span> <span class="number">533u</span><span class="identifier">s</span> 214<span class="identifier">Leaving</span> <span class="identifier">test</span> <span class="identifier">module</span> <span class="string">"example"</span><span class="special">;</span> <span class="identifier">testing</span> <span class="identifier">time</span><span class="special">:</span> <span class="number">643u</span><span class="identifier">s</span> 215 216<span class="special">***</span> <span class="number">1</span> <span class="identifier">failure</span> <span class="identifier">is</span> <span class="identifier">detected</span> <span class="identifier">in</span> <span class="identifier">the</span> <span class="identifier">test</span> <span class="identifier">module</span> <span class="string">"example"</span> 217</pre> 218 </td></tr></tbody> 219</table></div> 220<div class="note"><table border="0" summary="Note"> 221<tr> 222<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../../../doc/src/images/note.png"></td> 223<th align="left">Note</th> 224</tr> 225<tr><td align="left" valign="top"><p> 226 An <code class="computeroutput"><span class="identifier">assert</span><span class="special">(...)</span></code> 227 might call <code class="computeroutput"><span class="identifier">abort</span><span class="special">()</span></code>: 228 the use of the macros above may not be suitable for testing for <code class="computeroutput"><span class="identifier">assert</span></code>'s in a portable manner. 229 </p></td></tr> 230</table></div> 231<h5> 232<a name="boost_test.testing_tools.exception_correctness.h2"></a> 233 <span class="phrase"><a name="boost_test.testing_tools.exception_correctness.bibliographic_references"></a></span><a class="link" href="exception_correctness.html#boost_test.testing_tools.exception_correctness.bibliographic_references">Bibliographic 234 references</a> 235 </h5> 236<div class="variablelist"> 237<p class="title"><b>Publications</b></p> 238<dl class="variablelist"> 239<dt><span class="term"><a href="https://isocpp.org/wiki/faq/exceptions" target="_top">Exceptions and 240 Error Handling</a></span></dt> 241<dd><p> 242 Standard C++ Foundation 243 </p></dd> 244</dl> 245</div> 246</div> 247<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 248<td align="left"></td> 249<td align="right"><div class="copyright-footer">Copyright © 2001-2020 Boost.Test contributors<p> 250 Distributed under the Boost Software License, Version 1.0. (See accompanying 251 file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) 252 </p> 253</div></td> 254</tr></table> 255<hr> 256<div class="spirit-nav"> 257<a accesskey="p" href="extended_comparison/bitwise.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../testing_tools.html"><img src="../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="timeout.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> 258</div> 259</body> 260</html> 261
