[ cobertura-Feature Requests-1959691 ] Better Handling of Asserts

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Feature Requests item #1959691, was opened at 2008-05-07 11:18
Message generated for change (Comment added) made by dma_k
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Category: None
Group: None
Status: Open
Resolution: None
Priority: 6
Private: No
Submitted By: John Lewis (lewijw)
Assigned to: Nobody/Anonymous (nobody)
Summary: Better Handling of Asserts

Initial Comment:

Ian Dickinson wrote:

Sorry if this has been asked before; I did look in the archives but couldn't find anything.

I'm getting low branch coverage on code that includes java asserts to encode invariants. For example:

public void setFoo( String foo ) {
    assert foo != null;
    this.foo = foo;
}

@Test
public void testSetFoo() {
    new MockFoo.setFoo( "bar" );
}

@Test (expected=java.lang.AssertionError.class)
public void testSetFoo() {
    new MockFoo().setFoo( null );
}

I can execute both tests successfully, but cobertura will tell me that line with the assert was executed twice but did not traverse all branches.  I'm passing -ea to the JVM to enable the assertions, which I can see is working since the tests themselves all pass.

I'm using the cobertura 1.9 plugin for Maven2 on Java6 (I've tried both 6u6 and 6u4).

Any suggestions?

Thanks,
Ian

Jeffrey Bennett replied:

To get full coverage, you'd need to run 3 tests:
1.) Asserts off
2.) Asserts on, conditional true
3.) Asserts on, conditional false

You've done #2 and #3

To my knowledge, there's no good way of doing all 3 tests leading to a source of friction between Cobertura and asserts.

Ian replied:

OK, I understand. Would it be possible to have the branch coverage algorithm take this into account? I don't know if the VM args are captured in the .ser file, but if so it might be possible (I'm guessing here, I admit) for the branch coverage calculator to note that there are two possible worlds (your #1 vs #2 + #3), and depending which one is the "real" world adjust the statistics so that the code either tests one of the one possible branches, or two of the possible two.

And if that isn't impossible, can I make it a feature request please? :-)

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Comment By: Dmitry Katsubo (dma_k)
Date: 2012-05-10 12:38

Message:
+1
Sometimes assertions are impossible to cover, as they are too deep in the
code.

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Comment By: Alex Anderson (alexandergeorge)
Date: 2011-08-29 00:24

Message:
+1 also keen to see this feature

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Comment By: Ben Spiller (benspiller)
Date: 2011-08-26 04:42

Message:
+1 very keen on this feature - I want to encourage more of our developers
to add "assert" statements to code to check locking and conditional
invariants, but I don't want our code coverage to be reduced as a result! 

Simply adding an option to ignore assertion lines (so they're always 100%
green) would solve the problem and be greatly appreciated. 

Looks like this would be a popular feature:
http://stackoverflow.com/questions/4995471/cobertura-coverage-and-the-assert-keyword/
http://stackoverflow.com/questions/5111910/why-does-cobertura-fail-to-report-assert-branch-path-was-covered

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Comment By: Benjamin Croizet (graffity2199)
Date: 2010-04-16 07:48

Message:
+1 I also have low branch coverage because of asserts
This feature would be very interesting

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Comment By: Nobody/Anonymous (nobody)
Date: 2009-03-03 03:03

Message:
Hi,
Ditto - I'm using the Maven 2 plugin and would like to be able to disable
assertions for the surefire run that cobertura uses. I checked the source
and haven't found any obvious way... is there a known workaround (other
than doing it manually) for this?
Thanks!

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Comment By: Nobody/Anonymous (nobody)
Date: 2008-12-02 14:44

Message:
+1. At least provide an option to just automatically set assertion lines to
green or exclude/ignore them. It's simply not practical to do 1+2+3 as
described above.

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Comment By: Alan Gutierrez (alangutierrez)
Date: 2008-06-03 06:19

Message:
Logged In: YES 
user_id=2089590
Originator: NO

Please implement this feature. Ideally, Cobertura would not expect to see
#3 even when asserts were on. An assert is a condition that should never be
true. A very fruitless execerise to test the Java assert mechanism.

Certainly, running Cobertura with asserts off should only test #1 and not
expect #2 or #3.

I would be so happy to see this implemented.

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