diff --git a/lib/bamboo/test.ex b/lib/bamboo/test.ex
index a8319804..121cdaa4 100644
--- a/lib/bamboo/test.ex
+++ b/lib/bamboo/test.ex
@@ -1,6 +1,4 @@
 defmodule Bamboo.Test do
-  @timeout 100
-
   import ExUnit.Assertions
 
   @moduledoc """
@@ -159,33 +157,46 @@ defmodule Bamboo.Test do
       unsent_email = Bamboo.Email.new_email(subject: "something else")
       assert_delivered_email(unsent_email) # Will fail
   """
-  def assert_delivered_email(%Bamboo.Email{} = email) do
-    email = normalize_for_testing(email)
-    do_assert_delivered_email(email)
+  defmacro assert_delivered_email(email) do
+    quote do
+      import ExUnit.Assertions
+      email = Bamboo.Test.normalize_for_testing(unquote(email))
+      assert_receive({:delivered_email, ^email}, 100, Bamboo.Test.flunk_with_email_list(email))
+    end
   end
 
-  defp do_assert_delivered_email(email) do
-    receive do
-      {:delivered_email, ^email} -> true
-    after
-      @timeout -> flunk_with_email_list(email)
+  @doc """
+  Check whether an email's params are equal to the ones provided.
+
+  Must be used with the `Bamboo.TestAdapter` or this will never pass. In case you
+  are delivering from another process, the assertion waits up to 100ms before
+  failing. Typically if an email is successfully delivered the assertion will
+  pass instantly, so test suites will remain fast.
+
+  ## Examples
+
+      email = Bamboo.Email.new_email(subject: "something")
+      email |> MyApp.Mailer.deliver
+      assert_delivered_with(subject: "something") # Will pass
+
+      unsent_email = Bamboo.Email.new_email(subject: "something else")
+      assert_delivered_with(subject: "something else") # Will fail
+  """
+  defmacro assert_delivered_with(email_params) do
+    quote bind_quoted: [email_params: email_params] do
+      import ExUnit.Assertions
+      assert_receive({:delivered_email, email}, 100, Bamboo.Test.flunk_no_emails_received)
+
+      recieved_email_params = email |> Map.from_struct
+      assert Enum.all?(email_params, fn({k, v}) -> recieved_email_params[k] == v end),
+        Bamboo.Test.flunk_attributes_do_not_match(email_params, recieved_email_params) 
     end
   end
 
-  defp flunk_with_email_list(email) do
+  @doc false
+  def flunk_with_email_list(email) do
     if Enum.empty?(delivered_emails) do
-      flunk """
-      There were 0 emails delivered to this process.
-
-      If you expected an email to be sent, try these ideas:
-
-        1) Make sure you call deliver_now/1 or deliver_later/1 to deliver the email
-        2) Make sure you are using the Bamboo.TestAdapter
-        3) Use shared mode with Bamboo.Test. This will allow Bamboo.Test
-           to work across processes: use Bamboo.Test, shared: :true
-        4) If you are writing an acceptance test through a headless browser, use
-           shared mode as described in option 3.
-      """
+      flunk_no_emails_received
     else
       flunk """
       There were no matching emails.
@@ -201,6 +212,37 @@ defmodule Bamboo.Test do
     end
   end
 
+  @doc false
+  def flunk_no_emails_received do
+    flunk """
+    There were 0 emails delivered to this process.
+
+    If you expected an email to be sent, try these ideas:
+
+    1) Make sure you call deliver_now/1 or deliver_later/1 to deliver the email
+    2) Make sure you are using the Bamboo.TestAdapter
+    3) Use shared mode with Bamboo.Test. This will allow Bamboo.Test
+    to work across processes: use Bamboo.Test, shared: :true
+    4) If you are writing an acceptance test through a headless browser, use
+    shared mode as described in option 3.
+    """
+  end
+
+  @doc false
+  def flunk_attributes_do_not_match(params_given, params_received) do
+    """
+    The parameters given do not match.
+
+      Parameters given:
+
+        #{inspect params_given}
+
+      Email recieved:
+
+        #{inspect params_received}
+    """
+  end
+
   defp delivered_emails do
     {:messages, messages} = Process.info(self, :messages)
 
@@ -310,7 +352,8 @@ defmodule Bamboo.Test do
     !!Application.get_env(:bamboo, :shared_test_process)
   end
 
-  defp normalize_for_testing(email) do
+  @doc false
+  def normalize_for_testing(email) do
     email
     |> Bamboo.Mailer.normalize_addresses
     |> Bamboo.TestAdapter.clean_assigns
diff --git a/test/lib/bamboo/adapters/test_adapter_test.exs b/test/lib/bamboo/adapters/test_adapter_test.exs
index fedf307d..cc19b7b2 100644
--- a/test/lib/bamboo/adapters/test_adapter_test.exs
+++ b/test/lib/bamboo/adapters/test_adapter_test.exs
@@ -51,6 +51,14 @@ defmodule Bamboo.TestAdapterTest do
     assert_raise ExUnit.AssertionError, fn ->
       assert_delivered_email %{sent_email | to: "oops"}
     end
+
+    sent_email |> TestMailer.deliver_now
+    assert_delivered_with(from: {nil, "foo@bar.com"}) 
+
+    sent_email |> TestMailer.deliver_now
+    assert_raise ExUnit.AssertionError, fn ->
+      assert_delivered_with(from: "oops")
+    end
   end
 
   test "assert_delivered_email with no delivered emails" do
@@ -106,6 +114,33 @@ defmodule Bamboo.TestAdapterTest do
     end
   end
 
+  test "assert_delivered_with with no delivered emails" do
+    try do
+      assert_delivered_with from: {nil, "foo@bar.com"}
+    rescue
+      error in [ExUnit.AssertionError] ->
+        assert error.message =~ "0 emails delivered"
+    else
+      _ -> flunk "assert_delivered_email should have failed"
+    end
+  end
+
+  test "assert_delivered_with shows non-matching delivered email" do
+    sent_email = new_email(from: "foo@bar.com", to: ["foo@bar.com"])
+
+    sent_email |> TestMailer.deliver_now
+
+    try do
+      assert_delivered_with to: "oops"
+    rescue
+      error in [ExUnit.AssertionError] ->
+        assert error.message =~ "do not match"
+        assert error.message =~ sent_email.from
+    else
+      _ -> flunk "assert_delivered_email should have failed"
+    end
+  end
+
   test "assert_no_emails_delivered shows the delivered email" do
     sent_email = new_email(from: "foo@bar.com", to: ["foo@bar.com"])