We covered assertions a little in the exception handling document
which should be on the website but which I got from here:
http://svn.apache.org/viewvc/incubator/tuscany/site/src/site/xdoc/
exception_handling.html?view=co
To me, assertions are things that the developer declares should never
happen at runtime. As in, "I thought about it and decided this could
never happen but I decided to check anyway as I could be wrong."
Enabling them when running tests is necessary to verify those
assumptions.
This is different from things that should not happen but which might
through user error - like checking for a user passing in a null value
to an API call and throwing a IllegalArgumentException rather than
letting a NPE happen when you use the value.
And different from things that might quite realistically go wrong and
which your user should be informed about - such as an IOException
when reading from a file.
--
Jeremy
On Jul 20, 2006, at 3:33 PM, Raymond Feng wrote:
For those who are interested, there's a nice article about java
assertions @ http://www.javaworld.com/javaworld/jw-11-2001/jw-1109-
assert.html. And the following is quoted from it:
"Expressions within an assert statement should not produce side
effects, since doing so exposes program execution to potentially
different behavior with and without assertions enabled. You should
use assertions to produce more reliable programs, not less reliable
ones.
Finally, caution must guide the development of the expressions used
in assert statements. In addition to not producing side effects,
assertions should not alter normal program execution."
I think I buy what the author says.
Thanks,
Raymond
----- Original Message ----- From: "Yang ZHONG"
<[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Thursday, July 20, 2006 3:11 PM
Subject: Re: Java assertion related test case failures
I hope our code are not designated to run in some specifically
configured
JVM.
Since JVMs may turn assertion on or off, I'm not sure
AssertionError should
be an expected behavior in general.
Dedicated exceptions and errors are much better protocol, e.g.
IndexOutOfBoundsException and OutOfMemoryError give much more
specific/useful info than plain AssertionError, not to mention
assertion
isn't really born for error reporting.
On 7/20/06, Jeremy Boynes <[EMAIL PROTECTED]> wrote:
Assertions should be enabled when running our test cases.
I have added an AssertionTestCase to the spi module that will cause
the build to fail if assertions are not enabled.
--
Jeremy
On Jul 20, 2006, at 9:36 AM, Raymond Feng wrote:
> Hi,
>
> I ran into some test case failures with the trunk code in both
> Eclipse and Maven (reported by my continumm build) related to the
> usage of java assertions.
>
> For example, in test case
> "org.apache.tuscany.spi.extension.ReferenceTestCase", we have the
> following test:
>
> public void testPrepare() throws Exception {
> TestReference ref = new TestReference(null, null, null);
> try {
> ref.prepare(); //[rfeng] We assume the assert will catch
> null before it moves on to NPE
> fail();
> } catch (AssertionError e) {
> //expected // [rfeng] NPE is thrown if assertion is not
enabled
> }
> }
>
> By default, assertions are disabled by JVM unless you explicitly
> turned it on using "-ea" option on the VM (In Eclipse, you need to
> set the VM arguments either at the JRE or test case.profile level.
> For Maven, you may need to set MAVEN_OPTS to include -ea). As a
> result, the test case fails because it throws NullPointerException
> instead of AssertionError.
>
> Should we improve these test cases to be more robust?
>
> Thanks,
> Raymond
>
>
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Yang ZHONG
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