*testing.txt*	For Vim version 8.1.  Last change: 2019 Aug 04


		  VIM REFERENCE MANUAL	  by Bram Moolenaar


Testing Vim and Vim script			*testing-support*

Expression evaluation is explained in |eval.txt|.  This file goes into details
about writing tests in Vim script.  This can be used for testing Vim itself
and for testing plugins.

1. Testing Vim				|testing|
2. Test functions			|test-functions-details|
3. Assert functions			|assert-functions-details|

==============================================================================
1. Testing Vim						*testing*

Vim can be tested after building it, usually with "make test".
The tests are located in the directory "src/testdir".

There are several types of tests added over time:
	test33.in		oldest, don't add any of these
	test_something.in	old style tests
	test_something.vim	new style tests

						*new-style-testing*
New tests should be added as new style tests.  These use functions such as
|assert_equal()| to keep the test commands and the expected result in one
place.
						*old-style-testing*
In some cases an old style test needs to be used.  E.g. when testing Vim
without the |+eval| feature.

Find more information in the file src/testdir/README.txt.

==============================================================================
2. Test functions				*test-functions-details*

test_alloc_fail({id}, {countdown}, {repeat})		*test_alloc_fail()*
		This is for testing: If the memory allocation with {id} is
		called, then decrement {countdown}, and when it reaches zero
		let memory allocation fail {repeat} times.  When {repeat} is
		smaller than one it fails one time.


test_autochdir()					*test_autochdir()*
		Set a flag to enable the effect of 'autochdir' before Vim
		startup has finished.


test_feedinput({string})				*test_feedinput()*
		Characters in {string} are queued for processing as if they
		were typed by the user. This uses a low level input buffer.
		This function works only when with |+unix| or GUI is running.


test_garbagecollect_now()			 *test_garbagecollect_now()*
		Like garbagecollect(), but executed right away.  This must
		only be called directly to avoid any structure to exist
		internally, and |v:testing| must have been set before calling
		any function.


test_garbagecollect_soon()			 *test_garbagecollect_soon()*
		Set the flag to call the garbagecollector as if in the main
		loop.  Only to be used in tests.


test_getvalue({name})					*test_getvalue()*
		Get the value of an internal variable.  These values for
		{name} are supported:
			need_fileinfo


test_ignore_error({expr})			 *test_ignore_error()*
		Ignore any error containing {expr}.  A normal message is given
		instead.
		This is only meant to be used in tests, where catching the
		error with try/catch cannot be used (because it skips over
		following code).
		{expr} is used literally, not as a pattern.
		When the {expr} is the string "RESET" then the list of ignored
		errors is made empty.


test_null_blob()					*test_null_blob()*
		Return a |Blob| that is null. Only useful for testing.


test_null_channel()					*test_null_channel()*
		Return a |Channel| that is null. Only useful for testing.
		{only available when compiled with the +channel feature}


test_null_dict()					*test_null_dict()*
		Return a |Dict| that is null. Only useful for testing.


test_null_job()						*test_null_job()*
		Return a |Job| that is null. Only useful for testing.
		{only available when compiled with the +job feature}


test_null_list()					*test_null_list()*
		Return a |List| that is null. Only useful for testing.


test_null_partial()					*test_null_partial()*
		Return a |Partial| that is null. Only useful for testing.


test_null_string()					*test_null_string()*
		Return a |String| that is null. Only useful for testing.


test_option_not_set({name})				*test_option_not_set()*
		Reset the flag that indicates option {name} was set.  Thus it
		looks like it still has the default value. Use like this: >
			set ambiwidth=double
			call test_option_not_set('ambiwidth')
<		Now the 'ambiwidth' option behaves like it was never changed,
		even though the value is "double".
		Only to be used for testing!


test_override({name}, {val})				*test_override()*
		Overrides certain parts of Vim's internal processing to be able
		to run tests. Only to be used for testing Vim!
		The override is enabled when {val} is non-zero and removed
		when {val} is zero.
		Current supported values for name are:

		name	     effect when {val} is non-zero ~
		redraw       disable the redrawing() function
		redraw_flag  ignore the RedrawingDisabled flag
		char_avail   disable the char_avail() function
		starting     reset the "starting" variable, see below
		nfa_fail     makes the NFA regexp engine fail to force a
			     fallback to the old engine
		no_query_mouse  do not query the mouse position for "dec"
				terminals
		no_wait_return	set the "no_wait_return" flag.  Not restored
				with "ALL".
		ALL	     clear all overrides ({val} is not used)

		"starting" is to be used when a test should behave like
		startup was done.  Since the tests are run by sourcing a
		script the "starting" variable is non-zero. This is usually a
		good thing (tests run faster), but sometimes changes behavior
		in a way that the test doesn't work properly.
		When using: >
			call test_override('starting', 1)
<		The value of "starting" is saved.  It is restored by: >
			call test_override('starting', 0)


test_refcount({expr})					*test_refcount()*
		Return the reference count of {expr}.  When {expr} is of a
		type that does not have a reference count, returns -1.  Only
		to be used for testing.


test_scrollbar({which}, {value}, {dragging})		*test_scrollbar()*
		Pretend using scrollbar {which} to move it to position
		{value}.  {which} can be:
			left	Left scrollbar of the current window
			right	Right scrollbar of the current window
			hor	Horizontal scrollbar

		For the vertical scrollbars {value} can be 1 to the
		line-count of the buffer.  For the horizontal scrollbar the
		{value} can be between 1 and the maximum line length, assuming
		'wrap' is not set.

		When {dragging} is non-zero it's like dragging the scrollbar,
		otherwise it's like clicking in the scrollbar.
		Only works when the {which} scrollbar actually exists,
		obviously only when using the GUI.


test_setmouse({row}, {col})				*test_setmouse()*
		Set the mouse position to be used for the next mouse action.
		{row} and {col} are one based.
		For example: >
			call test_setmouse(4, 20)
			call feedkeys("\<LeftMouse>", "xt")


test_settime({expr})					*test_settime()*
		Set the time Vim uses internally.  Currently only used for
		timestamps in the history, as they are used in viminfo, and
		for undo.
		Using a value of 1 makes Vim not sleep after a warning or
		error message.
		{expr} must evaluate to a number.  When the value is zero the
		normal behavior is restored.

==============================================================================
3. Assert functions				*assert-functions-details*


assert_beeps({cmd})					*assert_beeps()*
		Run {cmd} and add an error message to |v:errors| if it does
		NOT produce a beep or visual bell.
		Also see |assert_fails()| and |assert-return|.

							*assert_equal()*
assert_equal({expected}, {actual} [, {msg}])
		When {expected} and {actual} are not equal an error message is
		added to |v:errors| and 1 is returned.  Otherwise zero is
		returned |assert-return|.
		There is no automatic conversion, the String "4" is different
		from the Number 4.  And the number 4 is different from the
		Float 4.0.  The value of 'ignorecase' is not used here, case
		always matters.
		When {msg} is omitted an error in the form "Expected
		{expected} but got {actual}" is produced.
		Example: >
	assert_equal('foo', 'bar')
<		Will result in a string to be added to |v:errors|:
	test.vim line 12: Expected 'foo' but got 'bar' ~

		Can also be used as a |method|: >
			mylist->assert_equal([1, 2, 3])


<							*assert_equalfile()*
assert_equalfile({fname-one}, {fname-two})
		When the files {fname-one} and {fname-two} do not contain
		exactly the same text an error message is added to |v:errors|.
		Also see |assert-return|.
		When {fname-one} or {fname-two} does not exist the error will
		mention that.
		Mainly useful with |terminal-diff|.

assert_exception({error} [, {msg}])			*assert_exception()*
		When v:exception does not contain the string {error} an error
		message is added to |v:errors|.  Also see |assert-return|.
		This can be used to assert that a command throws an exception.
		Using the error number, followed by a colon, avoids problems
		with translations: >
			try
			  commandthatfails
			  call assert_false(1, 'command should have failed')
			catch
			  call assert_exception('E492:')
			endtry

assert_fails({cmd} [, {error} [, {msg}]])			*assert_fails()*
		Run {cmd} and add an error message to |v:errors| if it does
		NOT produce an error.  Also see |assert-return|.
		When {error} is given it must match in |v:errmsg|.
		Note that beeping is not considered an error, and some failing
		commands only beep.  Use |assert_beeps()| for those.

assert_false({actual} [, {msg}])				*assert_false()*
		When {actual} is not false an error message is added to
		|v:errors|, like with |assert_equal()|.
		Also see |assert-return|.
		A value is false when it is zero. When {actual} is not a
		number the assert fails.
		When {msg} is omitted an error in the form
		"Expected False but got {actual}" is produced.

assert_inrange({lower}, {upper}, {actual} [, {msg}])	 *assert_inrange()*
		This asserts number and |Float| values.  When {actual}  is lower
		than {lower} or higher than {upper} an error message is added
		to |v:errors|.  Also see |assert-return|.
		When {msg} is omitted an error in the form
		"Expected range {lower} - {upper}, but got {actual}" is
		produced.

								*assert_match()*
assert_match({pattern}, {actual} [, {msg}])
		When {pattern} does not match {actual} an error message is
		added to |v:errors|.  Also see |assert-return|.

		{pattern} is used as with |=~|: The matching is always done
		like 'magic' was set and 'cpoptions' is empty, no matter what
		the actual value of 'magic' or 'cpoptions' is.

		{actual} is used as a string, automatic conversion applies.
		Use "^" and "$" to match with the start and end of the text.
		Use both to match the whole text.

		When {msg} is omitted an error in the form
		"Pattern {pattern} does not match {actual}" is produced.
		Example: >
	assert_match('^f.*o$', 'foobar')
<		Will result in a string to be added to |v:errors|:
	test.vim line 12: Pattern '^f.*o$' does not match 'foobar' ~

							*assert_notequal()*
assert_notequal({expected}, {actual} [, {msg}])
		The opposite of `assert_equal()`: add an error message to
		|v:errors| when {expected} and {actual} are equal.
		Also see |assert-return|.

		Can also be used as a |method|: >
			mylist->assert_notequal([1, 2, 3])

<							*assert_notmatch()*
assert_notmatch({pattern}, {actual} [, {msg}])
		The opposite of `assert_match()`: add an error message to
		|v:errors| when {pattern} matches {actual}.
		Also see |assert-return|.

assert_report({msg})					*assert_report()*
		Report a test failure directly, using {msg}.
		Always returns one.

assert_true({actual} [, {msg}])				*assert_true()*
		When {actual} is not true an error message is added to
		|v:errors|, like with |assert_equal()|.
		Also see |assert-return|.
		A value is TRUE when it is a non-zero number.  When {actual}
		is not a number the assert fails.
		When {msg} is omitted an error in the form "Expected True but
		got {actual}" is produced.


 vim:tw=78:ts=8:noet:ft=help:norl:
