activitypub: utils: add determine_explicit_mentions() and tests

test/web/activity_pub/utils_test.exs

@@ -0,0 +1,57 @@
+defmodule Pleroma.Web.ActivityPub.UtilsTest do
+  use Pleroma.DataCase
+  alias Pleroma.Web.ActivityPub.Utils
+
+  describe "determine_explicit_mentions()" do
+    test "works with an object that has mentions" do
+      object = %{
+        "tag" => [
+          %{
+            "type" => "Mention",
+            "href" => "https://example.com/~alyssa",
+            "name" => "Alyssa P. Hacker"
+          }
+        ]
+      }
+
+      assert Utils.determine_explicit_mentions(object) == ["https://example.com/~alyssa"]
+    end
+
+    test "works with an object that does not have mentions" do
+      object = %{
+        "tag" => [
+          %{"type" => "Hashtag", "href" => "https://example.com/tag/2hu", "name" => "2hu"}
+        ]
+      }
+
+      assert Utils.determine_explicit_mentions(object) == []
+    end
+
+    test "works with an object that has mentions and other tags" do
+      object = %{
+        "tag" => [
+          %{
+            "type" => "Mention",
+            "href" => "https://example.com/~alyssa",
+            "name" => "Alyssa P. Hacker"
+          },
+          %{"type" => "Hashtag", "href" => "https://example.com/tag/2hu", "name" => "2hu"}
+        ]
+      }
+
+      assert Utils.determine_explicit_mentions(object) == ["https://example.com/~alyssa"]
+    end
+
+    test "works with an object that has no tags" do
+      object = %{}
+
+      assert Utils.determine_explicit_mentions(object) == []
+    end
+
+    test "works with an object that has only IR tags" do
+      object = %{"tag" => ["2hu"]}
+
+      assert Utils.determine_explicit_mentions(object) == []
+    end
+  end
+end