diff --git a/lua/neotest/consumers/diagnostic.lua b/lua/neotest/consumers/diagnostic.lua
index 30191fa..928c7af 100644
--- a/lua/neotest/consumers/diagnostic.lua
+++ b/lua/neotest/consumers/diagnostic.lua
@@ -81,12 +81,10 @@ local function init(client)
       local pos_id = position.id
       local result = results[pos_id]
       if position.type == "test" and result and result.errors and #result.errors > 0 then
+        local pos_by_id = positions:get_key(pos_id)
+        local default_line = pos_by_id and pos_by_id:closest_value_for("range")[1]
         local placed = self.tracking_marks[pos_id]
-          or self:init_mark(
-            pos_id,
-            result.errors,
-            positions:get_key(pos_id):closest_value_for("range")[1]
-          )
+          or self:init_mark(pos_id, result.errors, default_line)
         if placed then
           for error_i, error in pairs(result.errors or {}) do
             local mark = api.nvim_buf_get_extmark_by_id(