diff --git a/test/service/workers/legacy_notifier_builder_test.exs b/test/service/workers/legacy_notifier_builder_test.exs
index 9b1f7b0c7..f648df6eb 100644
--- a/test/service/workers/legacy_notifier_builder_test.exs
+++ b/test/service/workers/legacy_notifier_builder_test.exs
@@ -16,7 +16,7 @@ defmodule Mobilizon.Service.Workers.LegacyNotifierBuilderTest do
   use Mobilizon.Tests.Helpers
   import Mox
   import Mobilizon.Factory
-  import Swoosh.TestAssertions
+  import Mobilizon.Tests.SwooshAssertions
 
   setup_all do
     Mox.defmock(NotifierMock, for: Mobilizon.Service.Notifier)
@@ -380,9 +380,9 @@ defmodule Mobilizon.Service.Workers.LegacyNotifierBuilderTest do
 
       LegacyNotifierBuilder.perform(%Oban.Job{args: args})
 
-      assert_email_sent(to: "user1@do.main")
-      refute_email_sent(to: "user2@do.main")
-      refute_email_sent(to: "user1@do.main")
+      assert_email_sent(%Swoosh.Email{to: [{"", "user1@do.main"}]})
+      refute_email_sent(%Swoosh.Email{to: [{"", "user2@do.main"}]})
+      refute_email_sent(%Swoosh.Email{to: [{"", "user1@do.main"}]})
     end
 
     test "sends emails to anonymous participants" do
@@ -425,9 +425,9 @@ defmodule Mobilizon.Service.Workers.LegacyNotifierBuilderTest do
 
       LegacyNotifierBuilder.perform(%Oban.Job{args: args})
 
-      assert_email_sent(to: "anon@mou.se")
-      refute_email_sent(to: "user2@do.main")
-      refute_email_sent(to: "anon@mou.se")
+      assert_email_sending(%Swoosh.Email{to: [{"", "anon@mou.se"}]}, 10_000)
+      refute_email_sent(%Swoosh.Email{to: [{"", "user2@do.main"}]})
+      refute_email_sent(%Swoosh.Email{to: [{"", "anon@mou.se"}]})
     end
   end
 end
diff --git a/test/support/swoosh_assertions.ex b/test/support/swoosh_assertions.ex
new file mode 100644
index 000000000..bdfc1bdbe
--- /dev/null
+++ b/test/support/swoosh_assertions.ex
@@ -0,0 +1,91 @@
+# The following module is taken from this issue
+# https://github.com/swoosh/swoosh/issues/488#issuecomment-1671224765
+
+defmodule Mobilizon.Tests.SwooshAssertions do
+  @moduledoc ~S"""
+  Assertions for emails.
+
+  The assertions provided by this module work by pattern matching
+  against all emails received by the test process against the
+  `Swoosh.Email` struct. For example:
+
+      assert_email_sent %{subject: "You got a message"}
+
+  If you want to be additionally explicit, you might:
+
+      assert_email_sent %Swoosh.Email{subject: "You got a message"}
+
+  If emails are being sent concurrently, you can use `assert_email_sending/2`:
+
+      assert_email_sending %{subject: "You got a message"}
+
+  Both functions will return the matched email if the assertion succeeds.
+  You can then perform further matches on it:
+
+      email = assert_email_sent %Swoosh.Email{subject: "You got a message"}
+      assert email.from == {"MyApp", "no-reply@example.com"}
+
+  Using pattern matching imposes two limitations. The first one is that you
+  must match precisely the Swoosh.Email structure. For example, the following
+  will not work:
+
+      assert_email_sent %{to: "foobar@example.com"}
+
+  That's because `Swoosh.Email` keeps the field as a list. This will work:
+
+      assert_email_sent %{to: [{"FooBar", "foobar@example.com"}]}
+
+  You are also not allowed to have interpolations. For example, the following
+  will not work:
+
+      assert_email_sent %{
+        subject: "You have been invited to #{org.name}",
+        to: [{user.name, user.email}]
+      }
+
+  However, you can rely on pattern matching and rewrite it as:
+
+      email = assert_email_sent %{subject: "You have been invited to " <> org_name}
+      assert org_name == org.name
+      assert email.to == [{user.name, user.email}]
+
+  """
+
+  @doc """
+  Matches an email has been sent.
+
+  See moduledoc for more information.
+  """
+  defmacro assert_email_sent(pattern) do
+    quote do
+      {:email, email} = assert_received({:email, unquote(pattern)})
+      email
+    end
+  end
+
+  @doc """
+  Matches an email is sending (within a timeout).
+
+  See moduledoc for more information.
+  """
+  defmacro assert_email_sending(
+             pattern,
+             timeout \\ Application.fetch_env!(:ex_unit, :assert_receive_timeout)
+           ) do
+    quote do
+      {:email, email} = assert_receive({:email, unquote(pattern)}, unquote(timeout))
+      email
+    end
+  end
+
+  @doc """
+  Refutes an email matching pattern has been sent.
+
+  The opposite of `assert_email_sent`.
+  """
+  defmacro refute_email_sent(pattern) do
+    quote do
+      refute_received({:email, unquote(pattern)})
+    end
+  end
+end