small refactoring

tests/test_emulator.py

@@ -203,6 +203,24 @@ def run_resize_cases():
     feed(stream, "\x1b[?1049l", False)
     assert max(screen.buffer[0]) < 8, sorted(screen.buffer[0])
 
+    # a shrink clamps the cursor (pyte does it via restore_cursor); without
+    # the clamp draw() writes to rows above or below the screen
+    proc, screen, stream = make(10, 8)
+    feed(stream, "\r\n".join("line{}".format(i) for i in range(8)), False)
+    feed(stream, "\x1b[1;1H", False)  # full screen, cursor at home
+    screen.resize(4, 10)
+    assert screen.cursor.y == 0, screen.cursor.y
+
+    proc, screen, stream = make(10, 8)
+    feed(stream, "top\x1b[7;1H", False)  # cursor on a blank row below content
+    screen.resize(4, 10)
+    assert screen.cursor.y == 3, screen.cursor.y
+
+    proc, screen, stream = make(20, 4)
+    feed(stream, "x" * 15, False)
+    screen.resize(4, 10)
+    assert screen.cursor.x == 10, screen.cursor.x
+
     # mode 2031 is how a live theme change reaches the app
     proc, screen, stream = make()
     assert not screen.theme_notify_enabled()
@@ -381,8 +399,7 @@ def run_clear_cases():
     assert len(screen.history) > 0, "history suppressed for too long"
 
     # ED 3 is app-driven: it clears scrollback and fires the clear callback,
-    # and (as in pyte/Terminus) also blanks the screen. Both agents pair it
-    # with 2J and repaint, so the render side must not wipe or nudge again.
+    # but (as in xterm, unlike pyte) leaves the visible screen alone
     cleared = []
     proc = FakeProcess()
     screen = VtScreen(10, 4, process=proc, clear_callback=lambda: cleared.append(1))
@@ -391,9 +408,10 @@ def run_clear_cases():
     assert len(screen.history) > 0
     feed(stream, "\x1b[3J", False)
     assert len(screen.history) == 0 and cleared, (len(screen.history), cleared)
+    assert screen.buffer[0][0].data == "a", screen.buffer[0][0]
 
-    # with erase_scrollback off, ED 3 still blanks the screen but the history
-    # and the view survive: agents repaint with it and would take both
+    # with erase_scrollback off, ED 3 is a no-op: agents repaint with it and
+    # would take the history and the view with them
     cleared = []
     proc = FakeProcess()
     screen = VtScreen(10, 4, process=proc, erase_scrollback=False,
@@ -405,7 +423,7 @@ def run_clear_cases():
     del cleared[:]  # the screen's own reset() fired one at construction
     feed(stream, "\x1b[3J", False)
     assert len(screen.history) == kept and not cleared, (len(screen.history), cleared)
-    assert screen.buffer[0][0].data == " ", screen.buffer[0][0]
+    assert screen.buffer[0][0].data == "a", screen.buffer[0][0]
 
     print("all clear-screen tests passed")
 

tests/test_imports.py

@@ -81,7 +81,7 @@ for entry in load_sublime_json("vterm.sublime-commands") + keymap:
 # every pending_* name mentioned in the modules must be a real Terminal
 # attribute, so a renamed flag cannot leave a writer pointing at nothing
 flags = {f for f in vars(Terminal(None)) if f.startswith("pending_")}
-assert flags == {"pending_clear", "pending_clear_screen"}, flags
+assert flags == {"pending_clear", "pending_clear_screen", "pending_render"}, flags
 for module in (commands, render, terminal_module):
     with open(module.__file__, encoding="utf-8") as f:
         # (?<!_) skips the private _pending_to_send_string write-queue flag

tests/test_render.py

@@ -595,10 +595,21 @@ line[2] = Char("x", "blue", "default")
 runs = [r for r in segment_buffer_line(line) if r[1] != r[2]]
 assert runs == [("漢", 0, 1, "red", "default", ""), ("x", 1, 2, "blue", "default", "")], runs
 
+# an orphaned wide-char filler (its wide half was overwritten with a narrow
+# char) still occupies a column: rendered as a space so later spans stay aligned
+line = StaticDefaultDict(Char(" "))
+line[0] = Char("a", "default", "default")
+line[1] = Char("", "red", "default")
+line[2] = Char("x", "blue", "default")
+runs = [r for r in segment_buffer_line(line) if r[1] != r[2]]
+assert runs == [("a", 0, 1, "default", "default", ""),
+                (" ", 1, 2, "red", "default", ""),
+                ("x", 2, 3, "blue", "default", "")], runs
+
 # reverse video swaps the pair, and default becomes reverse_default
 line = StaticDefaultDict(Char(" "))
 line[0] = Char("r", "red", "default", False, False, False, False, True)
 runs = [r for r in segment_buffer_line(line) if r[1] != r[2]]
 assert runs == [("r", 0, 1, "reverse_default", "red", "")], runs
 
-print("segmenter tests passed (leading gap, wide char, reverse)")
+print("segmenter tests passed (leading gap, wide char, orphan filler, reverse)")