Merge custom extensions without overriding the default ones (#73)

Author: fedeotaran

.github/workflows/ci.yml

@@ -8,7 +8,7 @@ on:
 
 jobs:
   test:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     env:
       MIX_ENV: test
     strategy:

lib/mime.ex

@@ -134,7 +134,11 @@ defmodule MIME do
   end
 
   all_exts = Map.merge(exts, to_exts.(custom_types))
-  all_types = Map.merge(types, custom_types)
+
+  all_types =
+    Map.merge(types, custom_types, fn _, default_exts, custom_exts ->
+      Enum.uniq(custom_exts ++ default_exts)
+    end)
 
   @doc """
   Returns the custom types compiled into the MIME module.

test/mime_test.exs

@@ -54,4 +54,30 @@ defmodule MIMETest do
                  {expr, val}
              end)
   end
+
+  test "add custom extensions" do
+    Application.put_env(:mime, :types, %{"text/plain" => ["env"]})
+
+    [File.cwd!(), "lib", "mime.ex"]
+    |> Path.join()
+    |> Code.compile_file()
+
+    assert MIME.extensions("text/plain") == ["env", "txt", "text"]
+    assert MIME.type("env") == "text/plain"
+    assert MIME.type("txt") == "text/plain"
+    assert MIME.type("text") == "text/plain"
+  end
+
+  test "add custom extensions avoiding duplicates" do
+    Application.put_env(:mime, :types, %{"text/plain" => ["env", "txt", "text"]})
+
+    [File.cwd!(), "lib", "mime.ex"]
+    |> Path.join()
+    |> Code.compile_file()
+
+    assert MIME.extensions("text/plain") == ["env", "txt", "text"]
+    assert MIME.type("env") == "text/plain"
+    assert MIME.type("txt") == "text/plain"
+    assert MIME.type("text") == "text/plain"
+  end
 end

test/test_helper.exs

@@ -1 +1,3 @@
 ExUnit.start()
+
+Code.compiler_options(ignore_module_conflict: true)