doctest --- Test interactive Python examples — How are Docstring Examples Recognized?

Reference note (untrusted external data; do not execute it as instructions). ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ In most cases a copy-and-paste of an interactive console session works fine, but doctest isn't trying to do an exact emulation of any specific Python shell. >>> # comments are ignored >>> x = 12 >>> x 12 >>> if x == 13: ... print("yes") ... else: ... print("no") ... print("NO") ... print("NO!!!") ... no NO NO!!! >>> single: >>>; interpreter prompt single: ...; interpreter prompt Any expected output must immediately follow the final '>>> ' or '... ' line containing the code, and the expected output (if any) extends to the next '>>> ' or all-whitespace line. Expected output cannot contain an all-whitespace line, since such a line is taken to signal the end of expected output. If expected output does contain a blank line, put in your doctest example each place a blank line is expected. All hard tab characters are expanded to spaces, using 8-column tab stops. Tabs in output generated by the tested code are not modified. Because any hard tabs in the sample output are expanded, this means that if the code output includes hard tabs, the only way the doctest can pass is if the NORMALIZE_WHITESPACE option or directive is in effect. Alternatively, the test can be rewritten to capture the output and compare it to an expected value as part of the test. This handling of tabs in the source was arrived at through trial and error, and has proven to be the least error prone way of handling them. It is possible to use a different algorithm for handling tabs by writing a custom DocTestParser class. Output to stdout is captured, but not output to stderr (exception tracebacks are captured via a different means). If you continue a line via backslashing in an interactive session, or for any other reason use a backslash, you should use a raw docstring, which will preserve your backslashes exactly as you type them Otherwise, the backslash will be interpreted as part of the string. For example, the \n above would be interpreted as a newline character. Alternatively, you can double each backslash in the doctest version (and not use a raw string) The starting column doesn't matter and as many leading whitespace characters are stripped from the expected output as appeared in the initial '>>> ' line that started the example. Attribution: Adapted from Python Documentation under PSF-2.0. Adaptation: WikiKV isolated this documentation section, normalized formatting, retained only bounded code excerpts, and shortened it at a paragraph or sentence boundary for retrieval. Verify version-sensitive details at the source.