add test for backoff

lib/pleroma/http/backoff.ex

@@ -28,7 +28,6 @@ def get(url, headers \\ [], options \\ []) do
     # this ensures that we don't hammer the server with requests, and instead wait for the backoff to expire
     # this is a very simple implementation, and can be improved upon!
     %{host: host} = URI.parse(url)
-
     case @cachex.get(@backoff_cache, host)  do
       {:ok, nil} ->
         case HTTP.get(url, headers, options) do

test/pleroma/http/backoff_test.exs

@@ -0,0 +1,34 @@
+defmodule Pleroma.HTTP.BackoffTest do
+  @backoff_cache :http_backoff_cache
+  use Pleroma.DataCase, async: false
+  alias Pleroma.HTTP.Backoff
+
+  describe "get/3" do
+    test "should return {:ok, env} when not rate limited" do
+      Tesla.Mock.mock_global(fn
+        %Tesla.Env{url: "https://akkoma.dev/api/v1/instance"} ->
+          {:ok, %Tesla.Env{status: 200, body: "ok"}}
+      end)
+      assert {:ok, env} = Backoff.get("https://akkoma.dev/api/v1/instance")
+      assert env.status == 200
+    end
+
+    test "should return {:error, env} when rate limited" do
+      # Shove a value into the cache to simulate a rate limit
+      Cachex.put(@backoff_cache, "akkoma.dev", true)
+      assert {:error, env} = Backoff.get("https://akkoma.dev/api/v1/instance")
+      assert env.status == 429
+    end
+
+    test "should insert a value into the cache when rate limited" do
+      Tesla.Mock.mock_global(fn
+        %Tesla.Env{url: "https://ratelimited.dev/api/v1/instance"} ->
+          {:ok, %Tesla.Env{status: 429, body: "Rate limited"}}
+      end)
+
+      assert {:error, env} = Backoff.get("https://ratelimited.dev/api/v1/instance")
+      assert env.status == 429
+      assert {:ok, true} = Cachex.get(@backoff_cache, "ratelimited.dev")
+  end
+  end
+end