test/vis: add a couple lua-vis interop tests

The tests assert that the entire file text is written to disk
even if mutated in a vis.events.FILE_SAVE_PRE hooks.

1 files changed, 7 insertions, 0 deletions

diff --git a/vis/interop/pre-save-shrinks.lua b/vis/interop/pre-save-shrinks.lua
new file mode 100644
index 0000000..d8a7e94
--- /dev/null
+++ b/vis/interop/pre-save-shrinks.lua
@@ -0,0 +1,7 @@
+vis.events.subscribe(vis.events.FILE_SAVE_PRE, function(file)
+	local lines = file.lines
+	for i=1, #lines do
+		lines[i] = lines[i]:sub(lines[i]:len()/2+1)
+	end
+	return true
+end)