[ruby/reline] Call #start_terminal after generating temporary inputrc

because inputrc will be read when starting up

https://github.com/ruby/reline/commit/0a30464385

test/reline/yamatanooroti/test_rendering.rb

@@ -6,7 +6,7 @@ begin
   class Reline::TestRendering < Yamatanooroti::TestCase
     def setup
       @pwd = Dir.pwd
-      @tmpdir = File.join(Dir.tmpdir, "test_reline_config_#{$$}")
+      @tmpdir = File.join(File.expand_path(Dir.tmpdir), "test_reline_config_#{$$}")
       begin
         Dir.mkdir(@tmpdir)
       rescue Errno::EEXIST
@@ -14,20 +14,20 @@ begin
         Dir.mkdir(@tmpdir)
       end
       Dir.chdir(@tmpdir)
-      inputrc_backup = ENV['INPUTRC']
-      @inputrc_file = ENV['INPUTRC'] = File.expand_path('temporaty_inputrc')
+      @inputrc_backup = ENV['INPUTRC']
+      @inputrc_file = ENV['INPUTRC'] = File.join(@tmpdir, 'temporaty_inputrc')
       File.unlink(@inputrc_file) if File.exist?(@inputrc_file)
-      start_terminal(5, 30, %W{ruby -I#{@pwd}/lib #{@pwd}/bin/multiline_repl})
-      sleep 0.5
-      ENV['INPUTRC'] = inputrc_backup
     end
 
     def teardown
       Dir.chdir(@pwd)
       FileUtils.rm_rf(@tmpdir)
+      ENV['INPUTRC'] = @inputrc_backup
     end
 
     def test_history_back
+      start_terminal(5, 30, %W{ruby -I#{@pwd}/lib #{@pwd}/bin/multiline_repl})
+      sleep 0.5
       write(":a\n")
       write("\C-p")
       close
@@ -40,6 +40,8 @@ begin
     end
 
     def test_backspace
+      start_terminal(5, 30, %W{ruby -I#{@pwd}/lib #{@pwd}/bin/multiline_repl})
+      sleep 0.5
       write(":abc\C-h\n")
       close
       assert_screen(<<~EOC)
@@ -51,6 +53,8 @@ begin
     end
 
     def test_autowrap
+      start_terminal(5, 30, %W{ruby -I#{@pwd}/lib #{@pwd}/bin/multiline_repl})
+      sleep 0.5
       write('01234567890123456789012')
       close
       assert_screen(<<~EOC)
@@ -59,6 +63,24 @@ begin
         2
       EOC
     end
+
+    def test_prompt
+      File.open(@inputrc_file, 'w') do |f|
+        f.write <<~'LINES'
+          "abc": "123"
+        LINES
+      end
+      start_terminal(5, 30, %W{ruby -I#{@pwd}/lib #{@pwd}/bin/multiline_repl})
+      sleep 0.5
+      write("abc\n")
+      close
+      assert_screen(<<~EOC)
+        Multiline REPL.
+        prompt> 123
+        => 123
+        prompt>
+      EOC
+    end
   end
 rescue LoadError, NameError
   # On Ruby repository, this test suit doesn't run because Ruby repo doesn't