Merge pull request #260 from abinoam/issue_43

Fix #43 - Ctrl-U (erase line) handling

lib/highline.rb

@@ -546,6 +546,9 @@ def get_line_raw_no_echo_mode(question)
         if character == "\b" || character == "\u007F"
           chopped = line.chop!
           output_erase_char if chopped && question.echo
+        elsif character == "\cU"
+          line.size.times { output_erase_char } if question.echo
+          line = ""
         elsif character == "\e"
           ignore_arrow_key
         else

test/test_highline.rb

@@ -349,6 +349,44 @@ def test_after_some_chars_backspace_does_not_enter_prompt_when_utf8
     assert_equal(4, @output.string.count("\b"))
   end
 
+  def test_erase_line_does_not_enter_prompt
+    @input << "\cU\cU\cU\cU\cU\cU\cU\cU\cU"
+    @input.rewind
+    answer = @terminal.ask("Please enter your password: ") do |q|
+      q.echo = "*"
+    end
+    assert_equal("", answer)
+    assert_equal("Please enter your password: \n", @output.string)
+
+    # There's no backspaces as the line is already empty
+    assert_equal(0, @output.string.count("\b"))
+  end
+
+  def test_after_some_chars_erase_line_does_not_enter_prompt_when_ascii
+    @input << "apple\cU\cU\cU\cU\cU\cU\cU\cU"
+    @input.rewind
+    answer = @terminal.ask("Please enter your password: ") do |q|
+      q.echo = "*"
+    end
+    assert_equal("", answer)
+
+    # There's only enough backspaces to clear the given string
+    assert_equal(5, @output.string.count("\b"))
+  end
+
+
+  def test_after_some_chars_erase_line_does_not_enter_prompt_when_utf8
+    @input << "maçã\cU\cU\cU\cU\cU\cU\cU\cU"
+    @input.rewind
+    answer = @terminal.ask("Please enter your password: ") do |q|
+      q.echo = "*"
+    end
+    assert_equal("", answer)
+
+    # There's only enough backspaces to clear the given string
+    assert_equal(4, @output.string.count("\b"))
+  end
+
   def test_readline_mode
     #
     # Rubinius (and JRuby) seems to be ignoring