Index text snapshots lazily by line

1 files changed, 26 insertions, 0 deletions

diff --git a/tests/run.lua b/tests/run.lua
index 8b29fd3..069cc60 100644
--- a/tests/run.lua
+++ b/tests/run.lua
@@ -1942,6 +1942,32 @@ test("TextView creation reads one operation-local snapshot", function()
   end, "immutable")
 end)
 
+test("TextView indexes only lines required by an operation", function()
+  local indexed = {}
+  local view = text_topology.new({ "aaa", "bbb", "ccc" }, "utf-8", {
+    splitter = function(text)
+      indexed[#indexed + 1] = text
+      return text_topology.split_editor_characters(text)
+    end,
+    encoder = function(character)
+      return character
+    end,
+  })
+
+  same(0, #indexed)
+  local positions = collect_iteration(view:iter_strict_forward(
+    domain.Position.new(2, 1),
+    domain.SearchScope.CURRENT_LINE
+  ))
+  list_same({ "(2,2)", "(2,3)" }, position_strings(positions))
+  list_same({ "bbb" }, indexed)
+  same("bb\nccc", view:text_suffix(domain.Position.new(2, 2)))
+  list_same({ "bbb" }, indexed)
+
+  same(3, view:line_character_count(1))
+  list_same({ "bbb", "aaa" }, indexed)
+end)
+
 test("All-empty buffers expose empty full-buffer iteration", function()
   local view = text_topology.new({ "", "", "" }, "utf-8")
   local bounds = view:buffer_match_start_bounds()