Option that enable to decide whether capture_io captures a prompt or not

Author: Yuki Ito

lib/ex_unit/lib/ex_unit/capture_io.ex

@@ -28,8 +28,9 @@ defmodule ExUnit.CaptureIO do
   named device like `:stderr` is also possible globally by
   giving the registered device name explicitly as argument.
 
-  When capturing of `:stdio`, this function captures a prompt,
-  otherwise do not.
+  When capturing of `:stdio` and the `:capture_prompt` option
+  is not `false`, this function captures a prompt, otherwise 
+  do not.
 
   A developer can set a string as an input. The default
   input is `:eof`.
@@ -42,36 +43,49 @@ defmodule ExUnit.CaptureIO do
       true
       iex> capture_io(:stderr, fn -> IO.write(:stderr, "josé") end) == "josé"
       true
-      iex> capture_io("this is input", fn->
+      iex> capture_io("this is input", fn ->
       ...>   input = IO.gets ">"
       ...>   IO.write input
       ...> end) == ">this is input"
       true
+      iex> capture_io([input: "this is input", capture_prompt: false], fn ->
+      ...>   input = IO.gets ">"
+      ...>   IO.write input
+      ...> end) == "this is input"
+      true
 
   """
-  def capture_io(device, input, fun) do
-    do_capture_io(map_dev(device), input, fun)
+  def capture_io(fun) do
+    do_capture_io(:standard_io, [], fun)
   end
 
   def capture_io(device, fun) when is_atom(device) do
-    do_capture_io(map_dev(device), "", fun)
+    capture_io(device, [], fun)
   end
 
   def capture_io(input, fun) when is_binary(input) do
-    do_capture_io(:standard_io, input, fun)
+    capture_io(:standard_io, [input: input], fun)
   end
 
-  def capture_io(fun) do
-    do_capture_io(:standard_io, "", fun)
+  def capture_io(options, fun) when is_list(options) do
+    capture_io(:standard_io, options, fun)
+  end
+
+  def capture_io(device, input, fun) when is_binary(input) do
+    capture_io(device, [input: input], fun)
+  end
+
+  def capture_io(device, options, fun) when is_list(options) do
+    do_capture_io(map_dev(device), options, fun)
   end
 
   defp map_dev(:stdio),  do: :standard_io
   defp map_dev(:stderr), do: :standard_error
   defp map_dev(other),   do: other
 
-  defp do_capture_io(:standard_io, input, fun) do
+  defp do_capture_io(:standard_io, options, fun) do
     original_gl = :erlang.group_leader
-    capture_gl = new_group_leader(self, input, true)
+    capture_gl = new_group_leader(self, options)
     :erlang.group_leader(capture_gl, self)
 
     try do
@@ -86,13 +100,15 @@ defmodule ExUnit.CaptureIO do
     end
   end
 
-  defp do_capture_io(device, input, fun) do
+  defp do_capture_io(device, options, fun) do
     unless original_io = Process.whereis(device) do
       raise "could not find IO device registered at #{inspect device}"
     end
 
+    options = Keyword.put(options, :capture_prompt, false)
+
     Process.unregister(device)
-    capture_io = new_group_leader(self, input)
+    capture_io = new_group_leader(self, options)
     Process.register(capture_io, device)
 
     try do
@@ -108,20 +124,19 @@ defmodule ExUnit.CaptureIO do
     end
   end
 
-  defp new_group_leader(runner, input, prompt_config // false) do
-    spawn_link(fn -> group_leader_process(runner, input, prompt_config) end)
+  defp new_group_leader(runner, options) do
+    spawn_link(fn -> group_leader_process(runner, options) end)
   end
 
-  defp group_leader_process(runner, input, prompt_config) do
+  defp group_leader_process(runner, options) do
+    prompt_config = Keyword.get(options, :capture_prompt, true)
+    input = Keyword.get(options, :input, "")
+
     register_input(input)
     register_prompt_config(prompt_config)
     group_leader_loop(runner, :infinity, [])
   end
 
-  defp register_input(nil) do
-    set_input(nil)
-  end
-
   defp register_input(input) do
     chars = :unicode.characters_to_list(input)
     set_input(chars)

lib/ex_unit/test/ex_unit/capture_io_test.exs

@@ -80,6 +80,10 @@ defmodule ExUnit.CaptureIOTest do
       :io.get_chars(">", 3)
     end) == ">"
 
+    assert capture_io([capture_prompt: false], fn ->
+      :io.get_chars(">", 3)
+    end) == nil
+
     capture_io(fn ->
       assert :io.get_chars(">", 3) == :eof
     end)
@@ -106,6 +110,10 @@ defmodule ExUnit.CaptureIOTest do
       :io.get_line ">"
     end) == ">"
 
+    assert capture_io([capture_prompt: false], fn ->
+      :io.get_line ">"
+    end) == nil
+
     capture_io(fn ->
       assert :io.get_line(">") == :eof
     end)
@@ -155,6 +163,10 @@ defmodule ExUnit.CaptureIOTest do
        :io.scan_erl_form('>')
     end) == ">>"
 
+    assert capture_io([capture_prompt: false], fn ->
+      :io.scan_erl_form('>')
+    end) == nil
+
     capture_io(fn ->
       assert :io.scan_erl_form('>') == { :eof, 1 }
     end)