FAQ entry critique (Re: Re: distinguishing between failures and errors)

Comments inline.

> Is this clearer?
> 
> ----
> 
> Q: What's the difference between a failure and an error?
> 
> A:
> 
> Assertions are used to check for the possibility of failures,
>  therefore failures are anticipated.  Errors are unanticipated 
> problems resulting in uncaught exceptions being propagated from a 
> JUnit test method. 
> 
> In the following example, the FileNotFoundException is expected and 
> checked with an assertion.  If the expected exception is not raised, 
> then a failure is produced.  If any other unexpected IOException or 
> unchecked exception (e.g. NullPointerException) is raised, the JUnit 
> framework catches the exception and signals an error.         
> 
>     public void testNonexistentFileRead() throws IOException {
>         try {
> 
>             File file = new File("doesNotExist.txt");
>             FileReader reader = new FileReader(file);
>             assertEquals('a', (char)reader.read());
>                       
>             fail("Should have thrown FileNotFoundException");

Suggestion: change the failure message to "Read from a nonexistent file?!". I 
prefer this pattern because it indicates what the system did incorrectly in a 
higher-level way. I also think it's funnier when I see it in the test 
results. ;)

--
J. B. Rainsberger,
President, Diaspar Software Services
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