Re: Linker error regarding importing and unit tests. Is this a bug?

[Daniel Davidson]

On Friday, 1 November 2013 at 12:59:24 UTC, Gary Willoughby wrote:
I have a small test case that displays a linker error. I 
wondered if this is an issue with the tool chain or whether i'm 
doing something wrong.

I have a simple directory structure like this:

test/methods.d
test/test1.d
test/test2.d

Here is the source code for the above modules:

methods.d:

        module test.methods;

        import std.array;

        public bool nothing(int[] x)
        {
                return x.empty();
        }

test1.d:

        module test.test1;

        struct S
        {
                int x[];
        }

        unittest
        {
                import test.methods;
                import std.stdio;

                writeln("test1 unit test");

                S s;

                assert(s.x.nothing());
        }

test2.d:

        module test.test2;

        import test.test1;

        struct T
        {
                int x[];
        }

I compile the following sources like this:

	rdmd --force -de -debug -I~/Desktop -m64 -main -property 
-unittest -w <file>

Where <file> is an individual file above. I do this because i 
like to compile and tests each module in isolation running the 
unit tests. When i try and compile `test2.d` i get the 
following error:

Undefined symbols for architecture x86_64:
  "_D4test7methods12__ModuleInfoZ", referenced from:
      _D4test5test112__ModuleInfoZ in test2.o
  "_D4test7methods7nothingFAiZb", referenced from:
      _D4test5test114__unittestL8_1FZv in test2.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to 
see invocation)

If i add the following to the bottom of `test2.d` it all 
compiles fine:

        unittest
        {
                import test.methods;
        }

Any idea what's going on here?

An alternative is to move the import statements in test1.d out of 
the unittest block, which becomes a function, to file scope. Then 
if you have multiple unittests in test1.d all are covered and the 
symbols are available.

...
version(unittest) {
  import methods;
}
unittest
{
  import std.stdio;
  writeln("test1 unit test");
  S s;
  assert(s.x.nothing());
}

Thanks
Dan