Google测试ASSERT_EQ无法编译

Question

I have a class, let's say it is named Foo in which I did not define an equality operator and I do not wish to define one (for my own reasons).

I wanted to test some functions which operate on Foo and I wrote the following code:

inline bool operator==(const Foo& left, const Foo& right)
{
   // here  I test my equality condition....
}

TEST(SomeTestCase, SomeTest)
{
    Foo expected = ...
    Foo actual = ...

    ASSERT_EQ(expected, actual);     // does NOT compile
    ASSERT_TRUE(expected == actual); // compiles without a problem
}

Does anybody know how can I make ASSERT_EQ compile, so that in case of failure it will print a meaningful error message?

I am using MSVC2012 and the error message is:

1>D:\3rdpartycache\CPP\gmock\1.6.0-2\sdk\gtest\include\gtest/gtest.h(1316): error C2784: 'bool testing::internal::operator ==(T *,const testing::internal::linked_ptr<T> &)' : could not deduce template argument for 'T *' from 'const Foo'
1>          D:\3rdpartycache\CPP\gmock\1.6.0-2\sdk\gtest\include\gtest/internal/gtest-linked_ptr.h(213) : see declaration of 'testing::internal::operator =='
1>          D:\3rdpartycache\CPP\gmock\1.6.0-2\sdk\gtest\include\gtest/gtest.h(1353) : see reference to function template instantiation 'testing::AssertionResult testing::internal::CmpHelperEQ<T1,T2>(const char *,const char *,const T1 &,const T2 &)' being compiled
1>          with
1>          [
1>              T1=Foo,
1>              T2=Foo
1>          ]
1>          OperationsOnFooTest.cpp(146) : see reference to function template instantiation 'testing::AssertionResult testing::internal::EqHelper<lhs_is_null_literal>::Compare<Foo,T>(const char *,const char *,const T1 &,const T2 &)' being compiled
1>          with
1>          [
1>              lhs_is_null_literal=false,
1>              T=Foo,
1>              T1=Foo,
1>              T2=Foo
1>          ]
1>          OperationsOnFooTest.cpp(146) : see reference to function template instantiation 'testing::AssertionResult testing::internal::EqHelper<lhs_is_null_literal>::Compare<Foo,T>(const char *,const char *,const T1 &,const T2 &)' being compiled
1>          with
1>          [
1>              lhs_is_null_literal=false,
1>              T=Foo,
1>              T1=Foo,
1>              T2=Foo
1>          ]

Answer 1

Try to verify that your operator== and Foo class are in same namespace. I experienced a similar error that solved this way.

You are right about the ASSERT_EQ compile error message though... not really helpful...