feat(webui): support image uploads in composer and message bubbles

tests/utils/test_media_decode.py

@@ -0,0 +1,75 @@
+"""Tests for ``nanobot.utils.media_decode``."""
+
+from __future__ import annotations
+
+import base64
+
+import pytest
+
+from nanobot.utils.media_decode import (
+    DEFAULT_MAX_BYTES,
+    FileSizeExceeded,
+    MAX_FILE_SIZE,
+    save_base64_data_url,
+)
+
+
+def _data_url(payload: bytes, mime: str = "image/png") -> str:
+    return f"data:{mime};base64,{base64.b64encode(payload).decode()}"
+
+
+def test_saves_png_with_correct_extension(tmp_path) -> None:
+    result = save_base64_data_url(_data_url(b"fake png"), tmp_path)
+    assert result is not None
+    assert result.endswith(".png")
+    assert (tmp_path / result.split("/")[-1]).read_bytes() == b"fake png"
+
+
+def test_returns_none_for_malformed_data_url(tmp_path) -> None:
+    assert save_base64_data_url("not-a-data-url", tmp_path) is None
+
+
+def test_returns_none_for_broken_base64(tmp_path) -> None:
+    # Python's b64decode strips non-alphabet chars by default, so we need a
+    # payload whose alphabet-filtered length breaks padding.
+    assert save_base64_data_url("data:image/png;base64,not-valid-base64!!!", tmp_path) is None
+
+
+def test_unknown_mime_falls_back_to_bin(tmp_path) -> None:
+    result = save_base64_data_url(_data_url(b"xyz", mime="unknown/type"), tmp_path)
+    assert result is not None
+    assert result.endswith(".bin")
+
+
+def test_default_limit_is_10mb(tmp_path) -> None:
+    """Backwards-compatible default — the API path depends on this."""
+    assert DEFAULT_MAX_BYTES == 10 * 1024 * 1024
+    assert MAX_FILE_SIZE == 10 * 1024 * 1024
+
+    oversized = b"x" * (11 * 1024 * 1024)
+    with pytest.raises(FileSizeExceeded, match="10MB limit"):
+        save_base64_data_url(_data_url(oversized), tmp_path)
+
+
+def test_explicit_max_bytes_overrides_default(tmp_path) -> None:
+    """WS channel passes 8 MB; a 9 MB payload should be rejected there even
+    though it would pass the 10 MB API limit."""
+    payload = b"y" * (9 * 1024 * 1024)
+    with pytest.raises(FileSizeExceeded, match="8MB limit"):
+        save_base64_data_url(_data_url(payload), tmp_path, max_bytes=8 * 1024 * 1024)
+
+
+def test_saved_file_lives_under_media_dir(tmp_path) -> None:
+    result = save_base64_data_url(_data_url(b"ok"), tmp_path)
+    assert result is not None
+    assert result.startswith(str(tmp_path))
+
+
+def test_legacy_symbols_reexported_from_api_server() -> None:
+    """Existing tests import ``_save_base64_data_url`` / ``_FileSizeExceeded``
+    from ``nanobot.api.server`` — keep the aliases working."""
+    from nanobot.api import server
+
+    assert server._save_base64_data_url is save_base64_data_url
+    assert server._FileSizeExceeded is FileSizeExceeded
+    assert server.MAX_FILE_SIZE == MAX_FILE_SIZE