doctest.testfile() confuses source detection

[nedbat]

Originally reported by Julian O (Bitbucket: oddthinking, GitHub: oddthinking)

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The doctest.testmod() method searches the current file for comments of a specific format, and runs them as a test. When I use that, coverage.py does an excellent job.

The doctest.testfile() method searches another file for the comments, and runs them as a test. When I use that, coverage.py complains that it is unable to find the source code.

I did not expect the .doctest file to give me a percentage coverage, but I did hope it would be able to understand the format of the filename, and to handle it gracefully.

Note: This is an different issue to <<issue 19>>.

Here is an example:

• File 1: factorial_testfile.py

  def factorial(n):
  """ Compute the factorial of a natural number."""

    if n == 0:
        return 1
    else:
        return n * factorial(n-1)
  

  if name == "main":
  import doctest
  doctest.testfile("factorial.doctest")

• File 2: factorial.doctest

  from factorial_testfile import factorial
  factorial(0)
  1
  factorial(1)
  1
  factorial(3)
  6

Here is what happens (under Windows, Python 2.6).

C:\temp\coveragetest>coverage run factorial_testfile.py

C:\temp\coveragetest>coverage report -m
Name                 Stmts   Exec  Cover   Missing
--------------------------------------------------
<doctest factorial   NoSource: No source for code: 'c:\\temp\\coveragetest\\<doctest factorial.doctest[0]>': [Errno 22] invalid mode ('rU') or filename: 'c:\\temp\\coveragetest\\<doctest factorial.doctest[0]>'
<doctest factorial   NoSource: No source for code: 'c:\\temp\\coveragetest\\<doctest factorial.doctest[3]>': [Errno 22] invalid mode ('rU') or filename: 'c:\\temp\\coveragetest\\<doctest factorial.doctest[3]>'
<doctest factorial   NoSource: No source for code: 'c:\\temp\\coveragetest\\<doctest factorial.doctest[1]>': [Errno 22] invalid mode ('rU') or filename: 'c:\\temp\\coveragetest\\<doctest factorial.doctest[1]>'
<doctest factorial   NoSource: No source for code: 'c:\\temp\\coveragetest\\<doctest factorial.doctest[2]>': [Errno 22] invalid mode ('rU') or filename: 'c:\\temp\\coveragetest\\<doctest factorial.doctest[2]>'
factorial_testfile       7      7   100%

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• Bitbucket: https://bitbucket.org/ned/coveragepy/issue/52

[nedbat]

This was fixed in <<changeset 9ef11bf7e50d (bb)>>.