diff --git a/lua/ivy/vim_mock.lua b/lua/ivy/vim_mock.lua
index 98f03fd..8f07472 100644
--- a/lua/ivy/vim_mock.lua
+++ b/lua/ivy/vim_mock.lua
@@ -1,9 +1,13 @@
 local mock = {
   commands = {},
+  lines = {},
+  cursors = {},
 }
 
 mock.reset = function()
   mock.commands = {}
+  mock.lines = {}
+  mock.cursors = {}
 
   _G.vim = {
     notify = function() end,
@@ -23,6 +27,44 @@ mock.reset = function()
       nvim_buf_set_option = function() end,
       nvim_buf_set_var = function() end,
       nvim_buf_set_keymap = function() end,
+      nvim_buf_delete = function() end,
+      nvim_buf_set_lines = function(buffer_number, state_index, end_index, _, items)
+        local new_lines = {}
+
+        for index = 1, state_index do
+          if mock.lines[buffer_number][index] == nil then
+            table.insert(new_lines, "")
+          else
+            table.insert(new_lines, mock.lines[buffer_number][index])
+          end
+        end
+
+        for index = 1, #items do
+          table.insert(new_lines, items[index])
+        end
+
+        if end_index ~= -1 then
+          error("Mock of nvim_buf_set_lines dose not support a end_index grater than -1 found " .. end_index)
+        end
+
+        mock.lines[buffer_number] = new_lines
+      end,
+      nvim_win_set_height = function() end,
+      nvim_win_set_cursor = function(window_number, position)
+        mock.cursors[window_number] = position
+      end,
+      nvim_buf_get_lines = function(buffer_number, start_index, end_index)
+        local lines = {}
+        for index = start_index, end_index do
+          table.insert(lines, mock.lines[buffer_number][index + 1])
+        end
+
+        if #lines == 0 then
+          return nil
+        end
+
+        return lines
+      end,
     },
   }
 end
diff --git a/lua/ivy/window_test.lua b/lua/ivy/window_test.lua
index 75b9698..c42b380 100644
--- a/lua/ivy/window_test.lua
+++ b/lua/ivy/window_test.lua
@@ -5,10 +5,19 @@ before_each(function()
   vim_mock.reset()
 end)
 
-it("can initialize", function(t)
+it("can initialize and destroy the window", function(t)
   window.initialize()
 
-  if window.get_buffer() ~= 10 then
-    t.error("The windows buffer should be 10 found " .. window.get_buffer())
-  end
+  t.assert_equal(10, window.get_buffer())
+  t.assert_equal(10, window.buffer)
+
+  window.destroy()
+  t.assert_equal(nil, window.buffer)
+end)
+
+it("can set items", function(t)
+  window.initialize()
+
+  window.set_items { { content = "Line one" } }
+  t.assert_equal("Line one", window.get_current_selection())
 end)
diff --git a/plugin/ivy.lua b/plugin/ivy.lua
index dcf5322..671d289 100644
--- a/plugin/ivy.lua
+++ b/plugin/ivy.lua
@@ -54,12 +54,12 @@ vim.api.nvim_create_user_command("IvyLines", function()
       local score = libivy.ivy_match(input, line)
       if score > -200 then
         local prefix = string.rep(" ", 4 - #tostring(index)) .. index .. ": "
-        table.insert(list, { score, prefix .. line })
+        table.insert(list, { score = score, content = prefix .. line })
       end
     end
 
     table.sort(list, function(a, b)
-      return a[1] < b[1]
+      return a.score < b.score
     end)
 
     return list
diff --git a/scripts/test.lua b/scripts/test.lua
index 8b69506..0574c55 100644
--- a/scripts/test.lua
+++ b/scripts/test.lua
@@ -42,6 +42,11 @@ _G.it = function(name, callback)
     error = function(message)
       error(message, 2)
     end,
+    assert_equal = function(expected, actual)
+      if expected ~= actual then
+        error("Failed to assert that '" .. expected .. "' matches '" .. actual .. "'", 2)
+      end
+    end,
   }
 
   call_hook "before_each"