chore: move when clause into pattern

lib/swoosh_mailinator.ex

@@ -43,11 +43,11 @@ defmodule Swoosh.Adapters.Mailinator do
   alias Swoosh.Email
   alias Swoosh.Mailer
 
-  def deliver(%Email{html_body: html, text_body: text} = email, _) when is_nil(html) do
+  def deliver(%Email{html_body: nil, text_body: _} = email, _) do
     email |> delegate
   end
 
-  def deliver(%Email{html_body: html, text_body: text} = email, _) when is_nil(text) do
+  def deliver(%Email{html_body: _, text_body: nil} = email, _) do
     email |> delegate
   end
 

test/swoosh_mlntr.exs

@@ -1,3 +1,5 @@
+# TODO rewrite with exunit
+
 Mix.install(
   [
     {:swoosh, "~> 1.7"},
@@ -35,6 +37,12 @@ defmodule Main do
     |> html_body(nil)
   end
 
+  def test_both_absent() do
+    prep()
+    |> Map.delete(:html_body)
+    |> Map.delete(:text_body)
+  end
+
   def prep do
     mess = "mess"
     new()
@@ -47,15 +55,24 @@ defmodule Main do
 
   def send(email) do
     email
-    |> IO.inspect()
     |> deliver([
       adapter: Swoosh.Adapters.Mailinator
     ])
   end
 end
 
-Main.test_both()      |> Main.send() |> IO.inspect()
+# ok cases
-Main.test_text_only() |> Main.send() |> IO.inspect()
+Main.test_both()      |> Main.send()
-Main.test_html_only() |> Main.send() |> IO.inspect()
+Main.test_text_only() |> Main.send()
-Main.test_text_nil()  |> Main.send() |> IO.inspect()
+Main.test_html_only() |> Main.send()
-Main.test_html_nil()  |> Main.send() |> IO.inspect()
+Main.test_text_nil()  |> Main.send()
+Main.test_html_nil()  |> Main.send()
+
+# failing cases
+try do
+  Main.test_both_absent() |> Main.send()
+rescue
+  FunctionClauseError -> "expected"
+else
+  _ -> "shoud have failed"
+end