From b76491ba8200d62ae532fa9fe74821ccb8190acd Mon Sep 17 00:00:00 2001
From: Eddie Lebow <elebow@users.noreply.github.com>
Date: Mon, 8 Mar 2021 23:51:27 -0500
Subject: [PATCH] Add tests for scrollback_fill_enlarged_window

---
 kitty_tests/__init__.py |  9 +++++++--
 kitty_tests/screen.py   | 42 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 49 insertions(+), 2 deletions(-)

diff --git a/kitty_tests/__init__.py b/kitty_tests/__init__.py
index 7aa272484..5626cf067 100644
--- a/kitty_tests/__init__.py
+++ b/kitty_tests/__init__.py
@@ -91,10 +91,15 @@ def set_options(self, options=None):
         options = Options(merge_configs(defaults._asdict(), final_options))
         set_options(options)
 
-    def create_screen(self, cols=5, lines=5, scrollback=5, cell_width=10, cell_height=20, options=None):
+    def create_screen(self, cols=5, lines=5, scrollback=5, cell_width=10, cell_height=20, options=None, content=tuple()):
         self.set_options(options)
         c = Callbacks()
-        return Screen(c, lines, cols, scrollback, cell_width, cell_height, 0, c)
+        s = Screen(c, lines, cols, scrollback, cell_width, cell_height, 0, c)
+        for content_line in content:
+            s.draw(content_line)
+            s.linefeed()
+            s.carriage_return()
+        return s
 
     def assertEqualAttributes(self, c1, c2):
         x1, y1, c1.x, c1.y = c1.x, c1.y, 0, 0
diff --git a/kitty_tests/screen.py b/kitty_tests/screen.py
index 0ac19d0b3..684ccb29d 100644
--- a/kitty_tests/screen.py
+++ b/kitty_tests/screen.py
@@ -303,6 +303,48 @@ def draw(text, end_line=True):
         s.resize(s.lines - 1, s.columns)
         self.ae(x_before, s.cursor.x)
 
+    def test_scrollback_fill_after_resize(self):
+        def prepare_screen(content=tuple()):
+            return self.create_screen(
+                lines=5,
+                cols=5,
+                options={'scrollback_fill_enlarged_window': True},
+                content=content,
+            )
+
+        def assert_lines(lines, s):
+            return self.ae(lines, str(s.linebuf).split("\n"))
+
+        # Height increased, width unchanged → pull down lines to fill new space at the top
+        s = prepare_screen([str(i) for i in range(0, 6)])
+        assert_lines(['2', '3', '4', '5', ''], s)
+        s.resize(7, s.columns)
+        assert_lines(['0', '1', '2', '3', '4', '5', ''], s)
+
+        # Height increased, width increased → rewrap, pull down
+        s = prepare_screen(['0', '1', '2', '3' * 15])
+        assert_lines(['2', '33333', '33333', '33333', ''], s)
+        s.resize(7, 12)
+        assert_lines(['0', '1', '2', '333333333333', '333', '', ''], s)
+
+        # Height increased, width decreased → rewrap, pull down if possible
+        s = prepare_screen(['0', '1', '2', '3' * 5])
+        assert_lines(['0', '1', '2', '33333', ''], s)
+        s.resize(6, 4)
+        assert_lines(['0', '1', '2', '3333', '3', ''], s)
+
+        # Height unchanged, width increased → rewrap, pull down if possible
+        s = prepare_screen(['0', '1', '2', '3' * 15])
+        assert_lines(['2', '33333', '33333', '33333', ''], s)
+        s.resize(s.lines, 12)
+        assert_lines(['1', '2', '333333333333', '333', ''], s)
+
+        # Height decreased, width increased → rewrap, pull down if possible
+        s = prepare_screen(['0', '1', '2', '3' * 15])
+        assert_lines(['2', '33333', '33333', '33333', ''], s)
+        s.resize(4, 12)
+        assert_lines(['2', '333333333333', '333', ''], s)
+
     def test_tab_stops(self):
         # Taken from vttest/main.c
         s = self.create_screen(cols=80, lines=2)