Fix enforcement of character limits

lib/pleroma/web/common_api/utils.ex

@@ -591,7 +591,7 @@ def validate_character_limit(full_payload, _attachments) do
     limit = Pleroma.Config.get([:instance, :limit])
     length = String.length(full_payload)
 
-    if length < limit do
+    if length <= limit do
       :ok
     else
       {:error, dgettext("errors", "The status is over the character limit")}

test/web/common_api/common_api_test.exs

@@ -202,13 +202,15 @@ test "it returns error when status is empty and no attachments" do
                CommonAPI.post(user, %{"status" => ""})
     end
 
-    test "it returns error when character limit is exceeded" do
+    test "it validates character limits are correctly enforced" do
       Pleroma.Config.put([:instance, :limit], 5)
 
       user = insert(:user)
 
       assert {:error, "The status is over the character limit"} =
                CommonAPI.post(user, %{"status" => "foobar"})
+
+      assert {:ok, activity} = CommonAPI.post(user, %{"status" => "12345"})
     end
 
     test "it can handle activities that expire" do