""" Tests for fix #677: auto-scroll override during streaming. The scroll system has a _scrollPinned flag and scrollIfPinned() to respect user scroll position. The bug was that scrollToBottom() was called unconditionally inside renderMessages() and appendThinking(), even during an active stream — overriding any scroll position the user had set. """ import pathlib import re REPO = pathlib.Path(__file__).parent.parent UI_JS = (REPO / "static" / "ui.js").read_text(encoding="utf-8") INDEX_HTML = (REPO / "static" / "index.html").read_text(encoding="utf-8") STYLE_CSS = (REPO / "static" / "style.css").read_text(encoding="utf-8") class TestScrollPinningFix: def test_render_messages_respects_active_stream(self): """renderMessages() must not call scrollToBottom() while streaming (#677). During an active stream, scrollToBottom() unconditionally re-pins scroll and overrides the user's position. renderMessages() must use scrollIfPinned() instead when S.activeStreamId is set. """ # Find renderMessages function rm_start = UI_JS.find("function renderMessages(") assert rm_start != -1, "renderMessages() not found in ui.js" rm_end = UI_JS.find("\nfunction ", rm_start + 1) rm_body = UI_JS[rm_start:rm_end] helper_start = UI_JS.find("function _scrollAfterMessageRender") assert helper_start != -1, "renderMessages scroll helper not found in ui.js" helper_end = UI_JS.find("\nfunction ", helper_start + 1) helper_body = UI_JS[helper_start:helper_end] # Must check activeStreamId before deciding which scroll fn to call assert "activeStreamId" in helper_body, ( "renderMessages() must check S.activeStreamId before scrolling — " "unconditional scrollToBottom() overrides user scroll position (#677)" ) # scrollIfPinned must be called through the renderMessages scroll policy (stream path) assert "_scrollAfterMessageRender(preserveScroll, scrollSnapshot);" in rm_body assert "scrollIfPinned()" in helper_body, ( "renderMessages() must call scrollIfPinned() during streaming (#677)" ) def test_append_thinking_uses_scroll_if_pinned(self): """appendThinking() must use scrollIfPinned() not scrollToBottom() (#677). appendThinking() fires continuously during streaming — calling scrollToBottom() inside it re-pins on every token, preventing the user from scrolling up. """ at_start = UI_JS.find("function appendThinking(") assert at_start != -1, "appendThinking() not found in ui.js" at_end = UI_JS.find("\nfunction ", at_start + 1) at_body = UI_JS[at_start:at_end] assert "scrollIfPinned()" in at_body, ( "appendThinking() must call scrollIfPinned() not scrollToBottom() (#677)" ) assert "scrollToBottom()" not in at_body, ( "appendThinking() must not call scrollToBottom() — it fires mid-stream (#677)" ) def test_scroll_threshold_increased(self): """Scroll re-pin threshold must be at least 150px (#677). 80px was too small — a fast mouse scroll wheel can jump 100–120px in one tick, causing unintended re-pin. 150px gives a proper dead zone. """ # Find the nearBottom assignment in the scroll listener near_bottom_pos = UI_JS.find("nearBottom=") if near_bottom_pos == -1: near_bottom_pos = UI_JS.find("nearBottom =") assert near_bottom_pos != -1, "nearBottom scroll threshold assignment not found" threshold_line = UI_JS[near_bottom_pos:near_bottom_pos + 120] # Extract the numeric threshold match = re.search(r"<\s*(\d+)", threshold_line) assert match, f"Numeric threshold not found near nearBottom assignment: {threshold_line!r}" threshold = int(match.group(1)) assert threshold >= 150, ( f"Scroll re-pin threshold is {threshold}px — must be >= 150px to avoid " f"hair-trigger re-pinning on fast scroll wheels (#677)" ) def test_scroll_to_bottom_button_exists_in_html(self): """index.html must contain a scroll-to-bottom button (#677). All major streaming chat UIs (Claude, ChatGPT) show a floating ↓ button when the user has scrolled up, giving a clear escape hatch to return to live output. """ assert "scrollToBottomBtn" in INDEX_HTML, ( "index.html must contain a #scrollToBottomBtn element (#677)" ) assert "scroll-to-bottom-btn" in INDEX_HTML, ( "index.html must use class scroll-to-bottom-btn for the scroll button (#677)" ) def test_scroll_to_bottom_button_hidden_by_default(self): """Scroll-to-bottom button must be hidden by default (display:none) (#677).""" btn_pos = INDEX_HTML.find("scrollToBottomBtn") assert btn_pos != -1 btn_context = INDEX_HTML[btn_pos:btn_pos + 200] assert "display:none" in btn_context or 'display="none"' in btn_context, ( "scrollToBottomBtn must be hidden by default — only shown when user scrolls up (#677)" ) def test_scroll_to_bottom_button_css_exists(self): """style.css must have styling for .scroll-to-bottom-btn (#677).""" assert ".scroll-to-bottom-btn" in STYLE_CSS, ( "style.css must define .scroll-to-bottom-btn styles (#677)" ) def test_scroll_to_bottom_button_is_overlayed(self): """Scroll-to-bottom button stays visible as an overlay outside transcript layout (#677).""" btn_css_pos = STYLE_CSS.find(".scroll-to-bottom-btn") assert btn_css_pos != -1 btn_css = STYLE_CSS[btn_css_pos:btn_css_pos + 300] assert "position:absolute" in btn_css, ( ".scroll-to-bottom-btn must be an overlay so it stays visible without " "participating in transcript scroll layout (#677)" ) def test_scroll_listener_hides_button_when_pinned(self): """Scroll listener must hide the button when user is near the bottom (#677).""" scroll_listener_start = UI_JS.find("el.addEventListener('scroll'") assert scroll_listener_start != -1, "scroll event listener not found" # After #1360 fix, the nearBottom + btn logic lives inside an rAF # callback — extend search window to cover the full listener block. listener_block = UI_JS[scroll_listener_start:scroll_listener_start + 600] assert "scrollToBottomBtn" in listener_block, ( "Scroll listener must show/hide scrollToBottomBtn based on _scrollPinned (#677)" ) def test_scroll_to_bottom_button_calls_scroll_to_bottom(self): """scrollToBottomBtn onclick must call scrollToBottom() (#677).""" btn_pos = INDEX_HTML.find("scrollToBottomBtn") assert btn_pos != -1 btn_context = INDEX_HTML[btn_pos:btn_pos + 200] assert "scrollToBottom()" in btn_context, ( "scrollToBottomBtn onclick must call scrollToBottom() (#677)" )