v2.7.6 (#600)

Co-authored-by: Clément Sirieix <clement.sirieix@mistral.ai>
Co-authored-by: Kim-Adeline Miguel <51720070+kimadeline@users.noreply.github.com>
Co-authored-by: Mathias Gesbert <mathias.gesbert@mistral.ai>
Co-authored-by: Maxime Dolores <maxime.dolores@ext.mistral.ai>
Co-authored-by: Michel Thomazo <51709227+michelTho@users.noreply.github.com>
Co-authored-by: Paul Cacheux <paul.cacheux@mistral.ai>
Co-authored-by: Quentin <quentin.torroba@mistral.ai>
Co-authored-by: Simon <80467011+sorgfresser@users.noreply.github.com>
Co-authored-by: angelapopopo <angele.lenglemetz@mistral.ai>
Co-authored-by: Mistral Vibe <vibe@mistral.ai>

tests/snapshots/test_ui_snapshot_streaming_code_fence.py

@@ -0,0 +1,61 @@
+"""Regression test for streaming code-fenced ASCII art rendering.
+
+Textual's Markdown.update() sets _last_parsed_line past fence openers,
+causing append() to re-parse without fence context and collapse content
+into paragraph text. This test streams a code-fenced diagram in small
+chunks and verifies the rendered output preserves the fence block.
+"""
+
+from __future__ import annotations
+
+from textual.pilot import Pilot
+
+from tests.conftest import build_test_agent_loop
+from tests.mock.utils import mock_llm_chunk
+from tests.snapshots.base_snapshot_test_app import BaseSnapshotTestApp, default_config
+from tests.snapshots.snap_compare import SnapCompare
+from tests.stubs.fake_backend import FakeBackend
+
+# Chunks are sized so the first one contains the fence opener (```)
+# plus content past the first newline — the exact pattern that triggers
+# the bug.
+_CHUNKS = [
+    # First chunk: fence opener + content past newline (triggers the bug)
+    "```\n  Client\n    |\n    |  POST",
+    " /api/orders\n    v\n+---------+\n| Gateway ",
+    "|\n+---------+\n    |\n    v\n+---------+\n| Service ",
+    "|\n+---------+\n    |\n    v\n+----+----+\n|   DB    ",
+    "|\n+---------+\n```",
+]
+
+
+class StreamingCodeFenceApp(BaseSnapshotTestApp):
+    def __init__(self) -> None:
+        config = default_config()
+        fake_backend = FakeBackend(
+            chunks=[mock_llm_chunk(content=chunk) for chunk in _CHUNKS]
+        )
+        super().__init__(config=config)
+        self.agent_loop = build_test_agent_loop(
+            config=config,
+            agent_name=self._current_agent_name,
+            enable_streaming=True,
+            backend=fake_backend,
+        )
+
+
+def test_snapshot_streaming_code_fence_preserved(snap_compare: SnapCompare) -> None:
+    """Verify that a streamed code-fenced diagram renders as a code block,
+    not as collapsed paragraph text.
+    """
+
+    async def run_before(pilot: Pilot) -> None:
+        await pilot.press(*"show diagram")
+        await pilot.press("enter")
+        await pilot.pause(0.5)
+
+    assert snap_compare(
+        "test_ui_snapshot_streaming_code_fence.py:StreamingCodeFenceApp",
+        terminal_size=(120, 36),
+        run_before=run_before,
+    )