newhook.h File Reference

Enable the use of special operator new that throws for testing. More...

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Namespaces
namespace	isc
	Defines the logger used by the top-level component of kea-lfc.
namespace	isc::util
namespace	isc::util::unittests

Detailed Description

Enable the use of special operator new that throws for testing.

This small utility allows a test case to force the global operator new to throw for a given size to test a case where memory allocation fails (which normally doesn't happen). To enable the feature, everything must be built with defining ENABLE_CUSTOM_OPERATOR_NEW beforehand, and set force_throw_on_new to true and throw_size_on_new to the size of data that should trigger the exception, immediately before starting the specific test that needs the exception.

Example:

 #include <util/unittests/newhook.h>
...
TEST(SomeTest, newException) {
       isc::util::unittests::force_throw_on_new = true;
       isc::util::unittests::throw_size_on_new = sizeof(Foo);
       try {
           // this will do 'new Foo()' internally and should throw
           createFoo();
           isc::util::unittests::force_throw_on_new = false;
           ASSERT_FALSE(true) << "Expected throw on new";
       } catch (const std::bad_alloc&) {
           isc::util::unittests::force_throw_on_new = false;
           // do some integrity check, etc, if necessary
       }
} 

Replacing the global operator new (and delete) is a dangerous technique, and triggering an exception solely based on the allocation size is not reliable, so this feature is disabled by default two-fold: The ENABLE_CUSTOM_OPERATOR_NEW build time variable, and run-time force_throw_on_new.

Definition in file newhook.h.