Add resizing filter to make sure pictures are not too big

Closes #810

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

test/web/upload/filter/resize_test.exs

@@ -0,0 +1,20 @@
+defmodule Mobilizon.Web.Upload.Filter.ResizeTest do
+  use Mobilizon.DataCase, async: true
+  alias Mobilizon.Web.Upload.Filter.Resize
+
+  test "does not resize if dimensions are ok" do
+    assert {100, 150} == Resize.limit_sizes({100, 150})
+  end
+
+  test "does resize only width if needed" do
+    assert {1_920, 960} == Resize.limit_sizes({2_000, 1_000})
+  end
+
+  test "does resize only height if needed" do
+    assert {540, 1_080} == Resize.limit_sizes({1_000, 2_000})
+  end
+
+  test "does resize if dimentions are really big, and keeps ratio" do
+    assert {724, 1080} == Resize.limit_sizes({10_050, 15_000})
+  end
+end