Question

Somewhat of an academic question, but I ran into this while writing some unit tests.

My unit test framework (UnitTest++) allows you to create structs to serve as fixtures. Usually these are customized to the tests in the file, so I put them at the top of my unit test file.

//Tests1.cpp

struct MyFixture {  MyFixture() { ... do some setup things ...} };

TEST_FIXTURE(MyFixture, SomeTest)
{
  ...
} 

//Tests2.cpp

struct MyFixture { MyFixture() { ... do some other setup things, different from Tests1}};

 TEST_FIXTURE(MyFixture, SomeOtherTest)
 {
  ...
 }

However, I found recently (with VS2005 at least) that when you name the fixture struct using the same name (so now two versions of the struct exist with the same name), then one of the versions is silently thrown out. This is pretty surprising, because I have my compiler set to /W4 (highest warning level) and no warning comes out. I guess this is a name clash, and why namespaces were invented, but do I really need to wrap each of my unit test fixtures in a separate namespace? I just want to make sure I’m not missing something more fundamental.

Is there a better way to fix this – should this be happening? Shouldn’t I be seeing a duplicate symbols error or something?

Answer 1

Try sticking the classes in an anonymous namespace, you may find it less distasteful than having to create and name a new namespace for each file.

Don’t have access to VS2005 and Cpp unit but this may work..

//Tests1.cpp
namespace
{
struct MyFixture {  MyFixture() { ... do some setup things ...} };
}

TEST_FIXTURE(MyFixture, SomeTest)
{
  ...
} 


//Tests2.cpp
namespace
{
struct MyFixture { MyFixture() { ... do some other setup things, different from Tests1}};
}

TEST_FIXTURE(MyFixture, SomeOtherTest)
{
 ...
}