chore: import upstream snapshot with attribution

tests/interactive_shell/runtime/test_spinner_state.py

@@ -0,0 +1,65 @@
+"""Tests for the inline turn spinner in runtime.core.state."""
+
+from __future__ import annotations
+
+import re
+import time
+
+from surfaces.interactive_shell.runtime.core.state import SpinnerState
+
+_GLYPHS = SpinnerState._SPINNER_FRAMES
+
+
+def _glyph(spinner: SpinnerState) -> str:
+    rendered = spinner.inline_spinner_ansi()
+    match = re.search("|".join(map(re.escape, _GLYPHS)), rendered)
+    assert match is not None, f"no spinner glyph in {rendered!r}"
+    return match.group(0)
+
+
+def test_spinner_frame_is_a_function_of_elapsed_time_not_call_count() -> None:
+    """Regression: the glyph must animate no matter how often it is rendered.
+
+    prompt_toolkit evaluates the prompt message callable several times per
+    render pass. A per-call frame counter advanced exactly one full cycle per
+    visible render (10 evals x 10 frames), so the on-screen glyph never
+    changed. Deriving the frame from elapsed time makes repeated evaluations
+    idempotent and guarantees the animation advances between renders.
+    """
+    spinner = SpinnerState()
+    spinner.start()
+
+    # Repeated evaluations inside one render pass: same frame every time.
+    first = _glyph(spinner)
+    assert all(_glyph(spinner) == first for _ in range(10))
+
+    # A frame interval later the glyph must have advanced.
+    spinner.started_at -= SpinnerState._FRAME_INTERVAL_S * 1.01
+    assert _glyph(spinner) != first
+
+    # Over a full cycle of elapsed time, every frame is visited in order.
+    spinner.start()
+    seen = []
+    for step in range(len(_GLYPHS)):
+        spinner.started_at = time.monotonic() - step * SpinnerState._FRAME_INTERVAL_S * 1.001
+        seen.append(_glyph(spinner))
+    assert seen == list(_GLYPHS)
+
+
+def test_spinner_renders_elapsed_seconds_and_cancel_hint() -> None:
+    spinner = SpinnerState()
+    spinner.start()
+    spinner.started_at = time.monotonic() - 8.2
+
+    rendered = spinner.inline_spinner_ansi()
+
+    assert "(8s)" in rendered
+    assert "esc to cancel" in rendered
+
+
+def test_spinner_empty_when_not_streaming() -> None:
+    spinner = SpinnerState()
+    assert spinner.inline_spinner_ansi() == ""
+    spinner.start()
+    spinner.stop()
+    assert spinner.inline_spinner_ansi() == ""