diff --git a/run-tests.sh b/run-tests.sh
index bf1874422..bd52f6100 100755
--- a/run-tests.sh
+++ b/run-tests.sh
@@ -34,6 +34,7 @@ fi
 
 t=$(mktemp -d)
 echo Temp dir: $t
+export ASEPRITE_USER_FOLDER=$t
 
 if [[ "$filter" == "" ]] || [[ "console" =~ $filter ]]; then
     echo ----------------------------------------------------------------------
diff --git a/scripts/app_preferences.lua b/scripts/app_preferences.lua
index c03b197c8..5737c86aa 100644
--- a/scripts/app_preferences.lua
+++ b/scripts/app_preferences.lua
@@ -22,10 +22,98 @@ end
 
 -- Preferences for documents
 do
+  local defPref = app.preferences.document(nil)
+  defPref.grid.bounds = Rectangle(0, 0, 16, 16)
+
   local s = Sprite(32, 32)
   local p = app.preferences.document(s)
+  assert(s.gridBounds == Rectangle(0, 0, 16, 16))
   assert(p.grid.bounds == Rectangle(0, 0, 16, 16))
   assert(p.grid.color == Color(0, 0, 255))
   p.grid.color = Color(255, 0, 0)
   assert(p.grid.color == Color(255, 0, 0))
 end
+
+-- Default & doc preferences combinations (related to https://community.aseprite.org/t/4305)
+do
+  -- Set default preferences
+  local defPref = app.preferences.document(nil)
+  defPref.grid.bounds = Rectangle(0, 0, 10, 10)
+  defPref.grid.color = Color(255, 255, 0) -- White
+  assert(defPref.grid.bounds == Rectangle(0, 0, 10, 10))
+  assert(defPref.grid.color == Color(255, 255, 0))
+
+  do -- File with default preferences
+    local doc = Sprite(32, 32)
+    local docPref = app.preferences.document(doc)
+    assert(doc.gridBounds == Rectangle(0, 0, 10, 10))
+    assert(docPref.grid.bounds == Rectangle(0, 0, 10, 10))
+    assert(docPref.grid.color == Color(255, 255, 0))
+    doc:saveAs('_test_pref.png')
+    doc:close()
+  end
+
+  do -- File with specific preferences
+    local doc = Sprite(32, 32)
+    local docPref = app.preferences.document(doc)
+    docPref.grid.color = Color(0, 128, 0)
+    assert(docPref.grid.bounds == Rectangle(0, 0, 10, 10))
+    assert(docPref.grid.color == Color(0, 128, 0))
+    doc:saveAs('_test_pref2.png')
+    doc:close()
+  end
+
+  -- Now we change default preferences
+  defPref.grid.bounds = Rectangle(0, 0, 64, 64)
+  defPref.grid.color = Color(255, 0, 0) -- Red
+  assert(defPref.grid.bounds == Rectangle(0, 0, 64, 64))
+  assert(defPref.grid.color == Color(255, 0, 0))
+  do -- A new document should have the new default preferences
+    local doc = Sprite(32, 32)
+    local docPref = app.preferences.document(doc)
+    assert(docPref.grid.bounds == Rectangle(0, 0, 64, 64))
+    assert(docPref.grid.color == Color(255, 0, 0))
+    doc:close()
+  end
+  do -- The first document should have the new default preferences (because it was saved with the defaults)
+
+    -- TODO maybe related to https://community.aseprite.org/t/grid-for-new-documents/3303
+    --      should we get the new defaults or the values when we saved the document?
+    --      (e.g. even if we didn't change the grid values, it looks
+    --      like if the user changed something about the grid or the
+    --      background colors, the expected behavior would be to
+    --      restore the exact same colors, no the new defaults)
+
+    local doc = Sprite{ fromFile="_test_pref.png" }
+    local docPref = app.preferences.document(doc)
+    assert(docPref.grid.bounds == Rectangle(0, 0, 64, 64))
+    assert(docPref.grid.color == Color(255, 0, 0))
+    doc:close()
+  end
+  do -- The second document should have the new specific preferences for the grid color
+    local doc = Sprite{ fromFile="_test_pref2.png" }
+    local docPref = app.preferences.document(doc)
+    assert(docPref.grid.bounds == Rectangle(0, 0, 64, 64))
+    assert(docPref.grid.color == Color(0, 128, 0))
+    doc:close()
+  end
+end
+
+do -- Test symmetry preferences
+  do -- File with default preferences
+    local doc = Sprite(200, 100)
+    local docPref = app.preferences.document(doc)
+    assert(docPref.symmetry.x_axis == 100)
+    assert(docPref.symmetry.y_axis == 50)
+    docPref.symmetry.x_axis = 25
+    doc:saveAs('_test_symmetry.png')
+    doc:close()
+  end
+  do -- File with default preferences
+    local doc = Sprite{ fromFile='_test_symmetry.png' }
+    local docPref = app.preferences.document(doc)
+    assert(docPref.symmetry.x_axis == 25)
+    assert(docPref.symmetry.y_axis == 50)
+    doc:close()
+  end
+end