Fails to use testFilename in unittest

[biocyberman via Digitalmars-d-learn]

This is the compile error message by the way:


dmd -unittest ./testFile.d                                        
                                                                   
                                                                   
                                                                   
         !6009

testFile.o: In function `_D8testFile14__unittestL4_1FZv':
./testFile.d:(.text._D8testFile14__unittestL4_1FZv+0x1a): 
undefined reference to `_D3std5stdio12testFilenameFNfAyamZAya'
collect2: error: ld returned 1 exit status
Error: linker exited with status 1