I use the following two lines as part of a make file associated with a unit test suite for the project I'm currently working on:

    perl.exe -MDevel::Cover t/Task.t
    c:\Perl\Site\bin\cover.bat -report html -outputdir C:\Users\Sample
+\CoverHtml
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The test file exercises Task.pm and the coverage results include coverage for Task.t, Task.pm and various other of my modules used by Task.pm.