kennethreitz/dive-into-python3
1
0
Fork 0
mirror of https://github.com/kennethreitz/dive-into-python3.git synced 2026-06-05 23:10:17 +00:00
Code Issues Packages Projects Releases Wiki Activity

'the answer' is not the answer

Browse Source
This commit is contained in:
Mark Pilgrim
2009-07-16 12:46:36 -04:00
parent c5aad49473
commit b141c11be9
4 changed files with 17 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files
unit-testing.html
+1 -1
View File
@@ -276,7 +276,7 @@ Ran 2 tests in 0.000s
FAILED (errors=1)</samp></pre>
<ol>
<li>You should have expected this to fail (since you haven&#8217;t written any code to pass it yet), but... it didn&#8217;t actually &#8220;fail,&#8221; it had an &#8220;error&#8221; instead. This is a subtle but important distinction. A unit test actually has <em>three</em> return values: pass, fail, and error. Pass, of course, means that the test passed&nbsp;&mdash;&nbsp;the code did what you expected. &#8220;Fail&#8221; is what the previous test case did (until you wrote code to make it pass)&nbsp;&mdash;&nbsp;it executed the code but the result was not what you expected. &#8220;Error&#8221; means that the code didn&#8217;t even execute properly.
<li>Why didn&#8217;t the code execute properly? The traceback gives the answer: the module you&#8217;re testing doesn&#8217;t have an exception called <code>OutOfRangeError</code>. Remember, you passed this exception to the <code>assertRaises()</code> method, because it&#8217;s the exception you want the function to raise given an out-of-range input. But the exception doesn&#8217;t exist, so the call to the <code>assertRaises()</code> method failed. It never got a chance to test the <code>to_roman()</code> function; it didn&#8217;t get that far.
<li>Why didn&#8217;t the code execute properly? The traceback tells all. The module you&#8217;re testing doesn&#8217;t have an exception called <code>OutOfRangeError</code>. Remember, you passed this exception to the <code>assertRaises()</code> method, because it&#8217;s the exception you want the function to raise given an out-of-range input. But the exception doesn&#8217;t exist, so the call to the <code>assertRaises()</code> method failed. It never got a chance to test the <code>to_roman()</code> function; it didn&#8217;t get that far.
</ol>
<p>To solve this problem, you need to define the <code>OutOfRangeError</code> exception in <code>roman2.py</code>.
<pre><code class=pp><a>class OutOfRangeError(ValueError): <span class=u>&#x2460;</span></a>