Commit 46c7a6f0 authored by Richard M. Stallman's avatar Richard M. Stallman
Browse files

(Test Coverage): New node.

parent fe45b975
...@@ -30,6 +30,7 @@ compiler, you need to know how to examine the compiler's input buffer. ...@@ -30,6 +30,7 @@ compiler, you need to know how to examine the compiler's input buffer.
* Debugger:: How the Emacs Lisp debugger is implemented. * Debugger:: How the Emacs Lisp debugger is implemented.
* Edebug:: A source-level Emacs Lisp debugger. * Edebug:: A source-level Emacs Lisp debugger.
* Syntax Errors:: How to find syntax errors. * Syntax Errors:: How to find syntax errors.
* Test Coverage:: Ensuring you have tested all branches in your code.
* Compilation Errors:: How to find errors that show up in byte compilation. * Compilation Errors:: How to find errors that show up in byte compilation.
@end menu @end menu
...@@ -738,6 +739,42 @@ the old indentation actually fits the intended nesting of parentheses, ...@@ -738,6 +739,42 @@ the old indentation actually fits the intended nesting of parentheses,
and you have put back those parentheses, @kbd{C-M-q} should not change and you have put back those parentheses, @kbd{C-M-q} should not change
anything. anything.
@node Test Coverage
@section Test Coverage
@cindex coverage testing
@findex testcover-start
@findex testcover-mark-all
@findex testcover-next-mark
You can do coverage testing for a file of Lisp code by first using
the command @kbd{M-x testcover-start @key{RET} @var{file} @key{RET}}
to instrument it. Then test your code by calling it one or more
times. Then use the command @kbd{M-x testcover-mark-all} to display
``splotches'' on the code to show where coverage is insufficient. The
command @kbd{M-x testcover-next-mark} will move point forward to the
next spot that has a splotch.
Normally, a red splotch indicates the form was never completely
evaluated; a brown splotch means it always evaluated to the same value
(meaning there has been little testing of what is done with the
result). However, the red splotch is skipped for forms that can't
possibly complete their evaluation, such as @code{error}. The brown
splotch is skipped for forms that are expected to always evaluate to
the same value, such as @code{(setq x 14)}.
For difficult cases, you can add do-nothing macros to your code to
give advice to the test coverage tool.
@defmac 1value form
Evaluate @var{form} and return its value, but inform coverage testing
that @var{form}'s value should always be the same.
@end defmac
@defmac noreturn form
Evaluate @var{form}, informing coverage testing that @var{form} should
never return. If it ever does return, you get a run-time error.
@end defmac
@node Compilation Errors @node Compilation Errors
@section Debugging Problems in Compilation @section Debugging Problems in Compilation
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