fix(test): make the _url_copy tests type-clean and machine-independent

tests/test_url_copy.py

@@ -3,6 +3,7 @@
 from __future__ import annotations
 
 import io
+from typing import cast
 
 import pytest
 from rich.console import Console
@@ -15,6 +16,18 @@ def _console() -> Console:
     return Console(file=io.StringIO(), force_terminal=True, width=80)
 
 
+def _output(console: Console) -> str:
+    """Everything a ``_console()`` was asked to print.
+
+    Rich declares ``Console.file`` as ``IO[str]``, which has no ``getvalue``,
+    so reading the buffer straight off the console is a type error (`ty`). The
+    cast narrows it back to the ``StringIO`` ``_console`` put there -- the same
+    idiom ``tests/test_output.py`` uses at its 23 read sites. Wrapped in a
+    helper here only because this file reads the buffer from several tests.
+    """
+    return cast(io.StringIO, console.file).getvalue()
+
+
 class _Recorder:
     def __init__(self) -> None:
         self.copied: list[str] = []
@@ -50,7 +63,13 @@ def test_detect_clipboard_linux_prefers_wl_copy(monkeypatch: pytest.MonkeyPatch)
     assert detect_clipboard() is not None
 
 
-def test_disabled_without_backend() -> None:
+def test_disabled_without_backend(monkeypatch: pytest.MonkeyPatch) -> None:
+    # `copier=None` means "detect one", NOT "there is none" (_url_copy.py:123),
+    # so the no-backend case has to be staged by making detection fail. Without
+    # this the test passes only on a machine with no clipboard command -- i.e.
+    # a bare CI container -- and fails for every developer on macOS (`pbcopy`
+    # is always there), Windows, WSL, or a Linux desktop.
+    monkeypatch.setattr(_url_copy, "detect_clipboard", lambda: None)
     wait = CopyableUrlWait(_console(), copier=None, interactive=True)
     assert wait.enabled is False
 
@@ -64,14 +83,16 @@ def test_on_prompt_prints_hint_when_enabled() -> None:
     console = _console()
     wait = CopyableUrlWait(console, copier=_Recorder(), interactive=True)
     wait.on_prompt("https://example.com/x")
-    assert "Press c to copy the link" in console.file.getvalue()
+    assert "Press c to copy the link" in _output(console)
 
 
-def test_on_prompt_silent_when_disabled() -> None:
+def test_on_prompt_silent_when_disabled(monkeypatch: pytest.MonkeyPatch) -> None:
+    # Same staging as test_disabled_without_backend: no detectable backend.
+    monkeypatch.setattr(_url_copy, "detect_clipboard", lambda: None)
     console = _console()
     wait = CopyableUrlWait(console, copier=None, interactive=True)
     wait.on_prompt("https://example.com/x")
-    assert console.file.getvalue() == ""
+    assert _output(console) == ""
 
 
 def test_wait_copies_on_c_keypress(monkeypatch: pytest.MonkeyPatch) -> None:
@@ -83,7 +104,7 @@ def test_wait_copies_on_c_keypress(monkeypatch: pytest.MonkeyPatch) -> None:
     monkeypatch.setattr(wait, "_read_key", lambda _timeout: next(keys, None))
     wait.wait(0.01)
     assert rec.copied == ["https://example.com/x"]
-    assert "Copied to clipboard" in console.file.getvalue()
+    assert "Copied to clipboard" in _output(console)
 
 
 def test_wait_copies_only_once(monkeypatch: pytest.MonkeyPatch) -> None: