[Cppunit-devel] assertion_traits<double> must be removed

[CppUnit d. m. l. <cpp...@li...>]

Hello,

The macro CPPUNIT_ASSERT_EQUAL uses a templated traits class,
CppUnit::assertion_traits<T> with member function equals() to test for =20
equality.
For the generic case, equals() is defined using operator=3D=3D(), which is
reasonable for most types.  Except for floating point.  Thus the macro
CPPUNIT_ASSERT_DOUBLES_EQUAL() is provided.  This macro does *NOT* use
assertion_traits<double>.  Rather, it uses special logic embodied in functio=
n
CppUnit::assertDoublesEquals().

Note that since there are no specializations of assertion_traits<> provided =
by
CppUnit, the user is free to define their own.  For example, I frequently
specialize assertion_traits<double>, defining equals() using a global =20
tolerance.

In revision 1.26 of include/cppunit/TestAssert.h, the specialization
assertion_traits<double> was introduced.  I propose that this is a mistake
that should be reverted.

The main reason is that one can no longer define one's own specialization.
Furthermore, contrary to the comment above it, assertion_traits<double>
is *NOT* used by CPPUNIT_ASSERT_DOUBLES_EQUAL.

Baptiste?

-Steve