Only run tests if epmd is available, closes #9167

Author: José Valim

lib/elixir/test/elixir/node_test.exs

@@ -5,7 +5,7 @@ defmodule NodeTest do
 
   doctest Node
 
-  @tag :unix
+  @tag :epmd
   test "start/3 and stop/0" do
     assert Node.stop() == {:error, :not_found}
     assert {:ok, _} = Node.start(:hello, :shortnames, 15000)

lib/elixir/test/elixir/test_helper.exs

@@ -84,10 +84,11 @@ defmodule CodeFormatterHelpers do
 end
 
 assert_timeout = String.to_integer(System.get_env("ELIXIR_ASSERT_TIMEOUT") || "500")
-exclude = if PathHelpers.windows?(), do: [unix: true], else: [windows: true]
+epmd_exclude = if match?({_, 0}, System.cmd("epmd", ["-daemon"])), do: [], else: [epmd: true]
+os_exclude = if PathHelpers.windows?(), do: [unix: true], else: [windows: true]
 
 ExUnit.start(
   trace: "--trace" in System.argv(),
   assert_receive_timeout: assert_timeout,
-  exclude: exclude
+  exclude: epmd_exclude ++ os_exclude
 )

lib/mix/test/mix/tasks/release_test.exs

@@ -265,6 +265,7 @@ defmodule Mix.Tasks.ReleaseTest do
     end)
   end
 
+  @tag :epmd
   test "executes rpc instructions" do
     in_fixture("release_test", fn ->
       config = [releases: [permanent1: [include_erts: false]]]

lib/mix/test/test_helper.exs

@@ -5,8 +5,9 @@ Application.put_env(:mix, :colors, enabled: false)
 Logger.remove_backend(:console)
 Application.put_env(:logger, :backends, [])
 
-exclude = if match?({:win32, _}, :os.type()), do: [unix: true], else: [windows: true]
-ExUnit.start(trace: "--trace" in System.argv(), exclude: exclude)
+os_exclude = if match?({:win32, _}, :os.type()), do: [unix: true], else: [windows: true]
+epmd_exclude = if match?({_, 0}, System.cmd("epmd", ["-daemon"])), do: [], else: [epmd: true]
+ExUnit.start(trace: "--trace" in System.argv(), exclude: epmd_exclude ++ os_exclude)
 
 unless {1, 7, 4} <= Mix.SCM.Git.git_version() do
   IO.puts(:stderr, "Skipping tests with git sparse checkouts...")