diff options
Diffstat (limited to 'Doc/lib')
| -rw-r--r-- | Doc/lib/libdoctest.tex | 73 |
1 files changed, 34 insertions, 39 deletions
diff --git a/Doc/lib/libdoctest.tex b/Doc/lib/libdoctest.tex index 0741aa0bfa..8951821376 100644 --- a/Doc/lib/libdoctest.tex +++ b/Doc/lib/libdoctest.tex @@ -235,57 +235,57 @@ Traceback (most recent call last): ValueError: list.remove(x): x not in list \end{verbatim} -That doctest succeeds if, and only if, \exception{ValueError} is raised, -with the \samp{list.remove(x): x not in list} detail as shown. +That doctest succeeds if \exception{ValueError} is raised, with the +\samp{list.remove(x): x not in list} detail as shown.\footnote{The + doctest also succeeds if it prints the exact text of the traceback + message; otherwise, it fails.} -The expected output for an exception is divided into four parts. -First, an example may produce some normal output before an exception -is raised, although that's unusual. The "normal output" is taken to -be everything until the first "Traceback" line, and is usually an -empty string. Next, the traceback line must be one of these two, and -indented the same as the first line in the example: +The expected output for an exception must start with a traceback +header, which may be either of the following two lines, indented the +same as the first line of the example: \begin{verbatim} Traceback (most recent call last): Traceback (innermost last): \end{verbatim} -The most interesting part is the last part: the line(s) starting with the -exception type and detail. This is usually the last line of a traceback, -but can extend across any number of lines. After the "Traceback" line, -doctest simply ignores everything until the first line indented the same as -the first line of the example, \emph{and} starting with an alphanumeric -character. This example illustrates the complexities that are possible: +The traceback header is followed by an optional traceback stack, whose +contents are ignored by doctest. Each line of the traceback stack +must be indented further than the first line of the example, \emph{or} +start with a non-alphanumeric character. Typically, the traceback +stack is either omitted or copied verbatim from an interactive +session. + +The traceback stack is followed by the most interesting part: the +line(s) containing the exception type and detail. This is usually the +last line of a traceback, but can extend across multiple lines if the +exception has a multi-line detail, as illustrated in the following +example: \begin{verbatim} ->>> print 1, 2; raise ValueError('printed 1\nand 2\n but not 3') -1 2 +>>> raise ValueError('multi\n line\ndetail') Traceback (most recent call last): -... indented the same, but doesn't start with an alphanumeric - not indented the same, so ignored too - File "/Python23/lib/doctest.py", line 442, in _run_examples_inner - compileflags, 1) in globs - File "<string>", line 1, in ? # and all these are ignored -ValueError: printed 1 -and 2 - but not 3 + File "<stdin>", line 1, in ? +ValueError: multi + line +detail \end{verbatim} -The first (\samp{1 2}) and last three (starting with -\exception{ValueError}) lines are compared, and the rest are ignored. +The last three (starting with \exception{ValueError}) lines are +compared against the exception's type and detail, and the rest are +ignored. -Best practice is to omit the ``File'' lines, unless they add +Best practice is to omit the traceback stack, unless it adds significant documentation value to the example. So the example above is probably better as: \begin{verbatim} ->>> print 1, 2; raise ValueError('printed 1\nand 2\n but not 3') -1 2 +>>> raise ValueError('multi\n line\ndetail') Traceback (most recent call last): - ... -ValueError: printed 1 -and 2 - but not 3 + ... +ValueError: multi + line +detail \end{verbatim} Note the tracebacks are treated very specially. In particular, in the @@ -293,11 +293,6 @@ rewritten example, the use of \samp{...} is independent of doctest's \constant{ELLIPSIS} option. The ellipsis in that example could be left out, or could just as well be three (or three hundred) commas. -\versionchanged[The abilities to check both normal output and an - exception in a single example, and to have a multi-line - exception detail, were added]{2.4} - - \subsection{Option Flags and Directives\label{doctest-options}} A number of option flags control various aspects of doctest's comparison @@ -634,7 +629,7 @@ Backslashes in a raw docstring: m\n \end{verbatim} Otherwise, the backslash will be interpreted as part of the string. - E.g., the "\textbackslash" above would be interpreted as a newline + E.g., the "{\textbackslash}" above would be interpreted as a newline character. Alternatively, you can double each backslash in the doctest version (and not use a raw string): |