Support ANSI escape sequence for clearing display in preview window

  fzf --preview 'for i in $(seq 100000); do
    (( i % 200 == 0 )) && printf "\033[2J"
    echo "$i"
    sleep 0.01
  done'

1 files changed, 6 insertions, 0 deletions

diff --git a/test/test_go.rb b/test/test_go.rb
index 2861235e..3ff118c1 100755
--- a/test/test_go.rb
+++ b/test/test_go.rb
@@ -1817,6 +1817,12 @@ class TestGoFZF < TestBase
     assert_equal %w[A Á], `#{echoes} | #{FZF} -f A`.lines.map(&:chomp)
     assert_equal %w[Á], `#{echoes} | #{FZF} -f Á`.lines.map(&:chomp)
   end
+
+  def test_preview_clear_screen
+    tmux.send_keys %{seq 100 | #{FZF} --preview 'for i in $(seq 300); do (( i % 200 == 0 )) && printf "\\033[2J"; echo "[$i]"; sleep 0.001; done'}, :Enter
+    tmux.until { |lines| lines.item_count == 100 }
+    tmux.until { |lines| lines[1]&.include?('[200]') }
+  end
 end
 
 module TestShell