Add small interactive test scripts

test_scripts/display_attr_lines_wiget.py

@@ -0,0 +1,38 @@
+import urwid
+import urwid.curses_display
+
+import cheuph
+from cheuph import AT, AttributedLines, AttributedLinesWidget
+
+
+class TestWidget(urwid.WidgetWrap):
+    def __init__(self):
+        lines = [
+                ({}, AT("a")),
+                ({}, AT("Hello world")),
+                ({}, AT("super long line " * 20)),
+        ]
+        self.lines = AttributedLinesWidget(AttributedLines(lines))
+        super().__init__(self.lines)
+
+    def selectable(self):
+        return True
+
+    def keypress(self, size, key):
+        if key == "left":
+            self.lines.horizontal_offset -= 1
+        elif key == "right":
+            self.lines.horizontal_offset += 1
+        elif key == "home":
+            self.lines.horizontal_offset = 0
+        elif key == "up":
+            self.lines.upper_offset += 1
+        elif key == "down":
+            self.lines.upper_offset -= 1
+
+def main():
+    screen = urwid.curses_display.Screen()
+    loop = urwid.MainLoop(TestWidget(), screen=screen)
+    loop.run()
+
+main()