I am not experienced with test, separated test scripts seems popular. So I am not sure what I think is good or bad. How about using pod comment like Test::inline? And use prove command of Test::Harness? I mean like this.

... contents of module
=test begin
ok(1==1, "1 test")
ok(2==2, "2 test")
=test end
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And grep this test.pl and test.

> cat test.pl |grep -v "^test" > testfile
> perl testfile; prove testfile
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regards