55 lines
2.3 KiB
Python
55 lines
2.3 KiB
Python
from pathlib import Path
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REPO = Path(__file__).resolve().parents[1]
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SESSIONS_JS = (REPO / "static" / "sessions.js").read_text(encoding="utf-8")
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def _function_body(src: str, signature: str) -> str:
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start = src.index(signature)
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brace = src.index("{", start)
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depth = 0
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for i in range(brace, len(src)):
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if src[i] == "{":
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depth += 1
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elif src[i] == "}":
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depth -= 1
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if depth == 0:
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return src[start : i + 1]
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raise AssertionError(f"function body not found: {signature}")
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def test_loading_older_messages_expands_render_window_before_rendering():
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body = _function_body(SESSIONS_JS, "async function _loadOlderMessages")
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prepend_idx = body.index("S.messages = [...olderMsgs, ...S.messages]")
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expand_idx = body.index("_messageRenderWindowSize=_currentMessageRenderWindowSize()")
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render_idx = body.index("renderMessages({ preserveScroll: true });")
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assert prepend_idx < expand_idx < render_idx, (
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"scroll-to-top paging must expand the DOM render window before renderMessages(); "
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"otherwise fetched older messages stay hidden and only the hidden counter changes"
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)
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assert "Math.max(addedRenderable, MESSAGE_RENDER_WINDOW_DEFAULT)" in body
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def test_loading_older_messages_preserves_viewport_without_bottom_snap():
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body = _function_body(SESSIONS_JS, "async function _loadOlderMessages")
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assert "renderMessages({ preserveScroll: true });" in body
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assert "const oldTop = container.scrollTop" in body
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assert "const addedHeight = Math.max(0, newScrollH - prevScrollH)" in body
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assert "container.scrollTop = oldTop + addedHeight" in body
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assert "container.scrollTop = newScrollH - prevScrollH" not in body
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restore_idx = body.index("container.scrollTop = oldTop + addedHeight")
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unpin_idx = body.rindex("_scrollPinned = false")
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assert restore_idx < unpin_idx
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def test_loading_older_messages_marks_scroll_programmatic_while_anchoring():
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body = _function_body(SESSIONS_JS, "async function _loadOlderMessages")
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set_idx = body.index("_programmaticScroll = true;")
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restore_idx = body.index("container.scrollTop = oldTop + addedHeight")
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clear_idx = body.index("requestAnimationFrame(()=>{ _programmaticScroll = false; })")
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assert set_idx < restore_idx < clear_idx
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