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 alloc_lines make a copy of every buffer line into allocated memory, so that memory access errors can be found by valgrind autoload import autoload will load the script right away, not postponed until an item is used char_avail disable the char_avail() function 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". redraw disable the redrawing() function redraw_flag ignore the RedrawingDisabled flag starting reset the "starting" variable, see below term_props reset all terminal properties when the version string is detected ui_delay time in msec to use in ui_delay(); overrules a wait time of up to 3 seconds for messages unreachable no error for code after :throw and :return uptime overrules sysinfo.uptime vterm_title setting the window title by a job running in a terminal window ALL clear all overrides, except alloc_lines ({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 this 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)

To make sure the flag is reset later using :defer can be useful:

call test_override('unreachable', 1)
defer call test_override('unreachable', 0)

Can also be used as a method:

GetOverrideVal()-> test_override('starting')