Add more tests to upload filters

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

lib/mobilizon/config.ex

@@ -276,17 +276,19 @@ defmodule Mobilizon.Config do
     end
   end
 
-  @spec put([module | atom], any) :: any
   def put([key], value), do: put(key, value)
 
   def put([parent_key | keys], value) do
-    parent = put_in(Application.get_env(:mobilizon, parent_key), keys, value)
+    parent =
+      Application.get_env(:mobilizon, parent_key, [])
+      |> put_in(keys, value)
 
     Application.put_env(:mobilizon, parent_key, parent)
   end
 
-  @spec put(module | atom, any) :: any
-  def put(key, value), do: Application.put_env(:mobilizon, key, value)
+  def put(key, value) do
+    Application.put_env(:mobilizon, key, value)
+  end
 
   @spec to_boolean(boolean | String.t()) :: boolean
   defp to_boolean(boolean), do: "true" == String.downcase("#{boolean}")

lib/mobilizon/utils.ex

@@ -0,0 +1,25 @@
+# Portions of this file are derived from Pleroma:
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Mobilizon.Utils do
+  @moduledoc """
+  Module that provide generic utils functions for Mobilizon
+  """
+
+  @doc """
+  POSIX-compliant check if command is available in the system
+
+  ## Examples
+      iex> command_available?("git")
+      true
+      iex> command_available?("wrongcmd")
+      false
+
+  """
+  @spec command_available?(String.t()) :: boolean()
+  def command_available?(command) do
+    match?({_output, 0}, System.cmd("sh", ["-c", "command -v #{command}"]))
+  end
+end