Manually build a unittest/doctest object in Python?

Question

If I have a string that is python code, for example

mycode = "print('hello world')"
myresult = "hello world"

How can a "manually" build a unittest (doctest) and test I get myresult

I have attempted to build a doctest but that is not working.

e = doctest.Example(source="print('hello world')/n", want="hello worldn")
t = doctest.DocTestRunner()
t.run(e)

Answer 1

Not easy. Effectively, you would have to re-invent the doctest module and re-engineer it to accept a completely different format.

But if you are willing to write your tests in doctest format, this might help you:

import doctest

def rundoctests(text, name='', globs=None, verbose=None,
 report=True, optionflags=0, extraglobs=None,
 raise_on_error=False,
 quiet=False,):
 # Assemble the globals.
 if globs is None:
 globs = globals()
 globs = globs.copy()
 if extraglobs is not None:
 globs.update(extraglobs)
 if '__name__' not in globs:
 globs['__name__'] = '__main__'
 # Parse the text looking for doc tests.
 parser = doctest.DocTestParser()
 test = parser.get_doctest(text, globs, name, name, 0)
 # Run the tests.
 if raise_on_error:
 runner = doctest.DebugRunner(
 verbose=verbose, optionflags=optionflags)
 else:
 runner = doctest.DocTestRunner(
 verbose=verbose, optionflags=optionflags)
 if quiet:
 runner.run(test, out=lambda s: None)
 else:
 runner.run(test)
 if report:
 runner.summarize()
 # Return a (named, if possible) tuple (failed, attempted).
 a, b = runner.failures, runner.tries
 try:
 TestResults = doctest.TestResults
 except AttributeError:
 return (a, b)
 return TestResults(a, b)

Then call rundoctests(text) to run any doc tests in text. By default, if there are no errors, it prints nothing. If there are errors, it prints the failing tests. Either way, it returns a tuple

(number of failures, number of tests run)

Examples in use:

py> good_code = """
... >>> import math
... >>> print "Hello World!"
... Hello World!
... >>> math.sqrt(100)
... 10.0
... 
... """
py> rundoctests(good_code)
TestResults(failed=0, attempted=3)

py> bad_code = """
... >>> print 10
... 11
... """
py> rundoctests(bad_code)
**********************************************************************
File "", line 2, in 
Failed example:
 print 10
Expected:
 11
Got:
 10
**********************************************************************
1 items had failures:
 1 of 1 in 
***Test Failed*** 1 failures.
TestResults(failed=1, attempted=1)