fix: mock _ensure_executable in mount tests for cross-platform compatibility

Commit 8738bbd added _ensure_executable() calls inside _find_copilot_cli()
but did not update the mount tests to mock it. The function calls os.access()
and os.stat() on fake test paths, which raises:
- WinError 3 on Windows (path not found)
- FileNotFoundError on Linux/macOS for non-existent paths

The broad `except Exception` in _find_copilot_cli silently swallows these
errors and returns None, causing 14 test failures on Windows and 7 on WSL.

Fix: Add patch("amplifier_module_provider_github_copilot._ensure_executable")
to all mount tests that expect _find_copilot_cli to return a valid path.

Affected files:
- tests/test_mount.py (10 tests)
- tests/test_mount_coverage.py (7 tests)

Verified: 29/29 mount tests pass on Windows, WSL, and macOS.

Author: Mowri M

tests/test_mount.py

@@ -20,14 +20,15 @@ async def test_mount_success(self, mock_coordinator):
         with patch("shutil.which", return_value="/usr/bin/copilot"):
             with patch("os.path.isfile", return_value=True):
                 with patch("os.path.isabs", return_value=True):
-                    cleanup = await mount(mock_coordinator, {"model": "claude-opus-4.5"})
+                    with patch("amplifier_module_provider_github_copilot._ensure_executable"):
+                        cleanup = await mount(mock_coordinator, {"model": "claude-opus-4.5"})
 
-                    # Should return cleanup function
-                    assert cleanup is not None
-                    assert callable(cleanup)
+                        # Should return cleanup function
+                        assert cleanup is not None
+                        assert callable(cleanup)
 
-                    # Provider should be mounted
-                    assert "github-copilot" in mock_coordinator.mounted_providers
+                        # Provider should be mounted
+                        assert "github-copilot" in mock_coordinator.mounted_providers
 
     @pytest.mark.asyncio
     async def test_mount_missing_cli(self, mock_coordinator):
@@ -47,60 +48,64 @@ async def test_mount_with_custom_cli_path(self, mock_coordinator):
         with patch("shutil.which") as mock_which:
             with patch("os.path.isfile", return_value=True):
                 with patch("os.path.isabs", return_value=True):
-                    mock_which.return_value = "/custom/path/copilot"
+                    with patch("amplifier_module_provider_github_copilot._ensure_executable"):
+                        mock_which.return_value = "/custom/path/copilot"
 
-                    cleanup = await mount(
-                        mock_coordinator,
-                        {"cli_path": "/custom/path/copilot"},
-                    )
+                        cleanup = await mount(
+                            mock_coordinator,
+                            {"cli_path": "/custom/path/copilot"},
+                        )
 
-                    assert cleanup is not None
+                        assert cleanup is not None
 
     @pytest.mark.asyncio
     async def test_mount_cleanup_function(self, mock_coordinator):
         """Cleanup function should close provider."""
         with patch("shutil.which", return_value="/usr/bin/copilot"):
             with patch("os.path.isfile", return_value=True):
                 with patch("os.path.isabs", return_value=True):
-                    cleanup = await mount(mock_coordinator, {})
+                    with patch("amplifier_module_provider_github_copilot._ensure_executable"):
+                        cleanup = await mount(mock_coordinator, {})
 
-                    assert cleanup is not None
+                        assert cleanup is not None
 
-                    # Get the mounted provider
-                    provider = mock_coordinator.mounted_providers.get("github-copilot")
-                    assert provider is not None
+                        # Get the mounted provider
+                        provider = mock_coordinator.mounted_providers.get("github-copilot")
+                        assert provider is not None
 
-                    # Mock the provider's close method
-                    with patch.object(provider, "close", new_callable=AsyncMock) as mock_close:
-                        await cleanup()
-                        mock_close.assert_called_once()
+                        # Mock the provider's close method
+                        with patch.object(provider, "close", new_callable=AsyncMock) as mock_close:
+                            await cleanup()
+                            mock_close.assert_called_once()
 
     @pytest.mark.asyncio
     async def test_mount_default_config(self, mock_coordinator):
         """Mount should work with no config (uses defaults)."""
         with patch("shutil.which", return_value="/usr/bin/copilot"):
             with patch("os.path.isfile", return_value=True):
                 with patch("os.path.isabs", return_value=True):
-                    cleanup = await mount(mock_coordinator, None)
+                    with patch("amplifier_module_provider_github_copilot._ensure_executable"):
+                        cleanup = await mount(mock_coordinator, None)
 
-                    assert cleanup is not None
-                    provider = mock_coordinator.mounted_providers.get("github-copilot")
-                    assert provider._model == "claude-opus-4.5"  # Default model
+                        assert cleanup is not None
+                        provider = mock_coordinator.mounted_providers.get("github-copilot")
+                        assert provider._model == "claude-opus-4.5"  # Default model
 
     @pytest.mark.asyncio
     async def test_mount_registers_with_coordinator(self, mock_coordinator):
         """Mount should call coordinator.mount with correct arguments."""
         with patch("shutil.which", return_value="/usr/bin/copilot"):
             with patch("os.path.isfile", return_value=True):
                 with patch("os.path.isabs", return_value=True):
-                    await mount(mock_coordinator, {})
+                    with patch("amplifier_module_provider_github_copilot._ensure_executable"):
+                        await mount(mock_coordinator, {})
 
-                    # Verify mount was called
-                    mock_coordinator.mount.assert_called_once()
-                    call_args = mock_coordinator.mount.call_args
+                        # Verify mount was called
+                        mock_coordinator.mount.assert_called_once()
+                        call_args = mock_coordinator.mount.call_args
 
-                    assert call_args[0][0] == "providers"  # category
-                    assert call_args[1]["name"] == "github-copilot"
+                        assert call_args[0][0] == "providers"  # category
+                        assert call_args[1]["name"] == "github-copilot"
 
 
 class TestModuleMetadata:
@@ -152,15 +157,16 @@ async def test_mount_returns_none_on_provider_init_error(self, mock_coordinator)
         with patch("shutil.which", return_value="/usr/bin/copilot"):
             with patch("os.path.isfile", return_value=True):
                 with patch("os.path.isabs", return_value=True):
-                    # Make coordinator.mount raise during provider registration
-                    mock_coordinator.mount = AsyncMock(
-                        side_effect=RuntimeError("Mount failed: config error")
-                    )
+                    with patch("amplifier_module_provider_github_copilot._ensure_executable"):
+                        # Make coordinator.mount raise during provider registration
+                        mock_coordinator.mount = AsyncMock(
+                            side_effect=RuntimeError("Mount failed: config error")
+                        )
 
-                    cleanup = await mount(mock_coordinator, {})
+                        cleanup = await mount(mock_coordinator, {})
 
-                    # Should return None (graceful degradation)
-                    assert cleanup is None
+                        # Should return None (graceful degradation)
+                        assert cleanup is None
 
 
 class TestFindCopilotCli:
@@ -172,9 +178,10 @@ def test_cli_from_config(self):
 
         with patch("os.path.isabs", return_value=True):
             with patch("os.path.isfile", return_value=True):
-                result = _find_copilot_cli({"cli_path": "/custom/copilot"})
+                with patch("amplifier_module_provider_github_copilot._ensure_executable"):
+                    result = _find_copilot_cli({"cli_path": "/custom/copilot"})
 
-                assert result == "/custom/copilot"
+                    assert result == "/custom/copilot"
 
     def test_cli_from_env_var(self):
         """_find_copilot_cli should check COPILOT_CLI_PATH env var."""
@@ -183,9 +190,10 @@ def test_cli_from_env_var(self):
         with patch.dict("os.environ", {"COPILOT_CLI_PATH": "/env/copilot"}):
             with patch("os.path.isabs", return_value=True):
                 with patch("os.path.isfile", return_value=True):
-                    result = _find_copilot_cli({})
+                    with patch("amplifier_module_provider_github_copilot._ensure_executable"):
+                        result = _find_copilot_cli({})
 
-                    assert result == "/env/copilot"
+                        assert result == "/env/copilot"
 
     def test_cli_from_shutil_which(self):
         """_find_copilot_cli should fall back to shutil.which()."""
@@ -195,9 +203,10 @@ def test_cli_from_shutil_which(self):
             with patch("shutil.which", return_value="/usr/bin/copilot"):
                 with patch("os.path.isabs", return_value=True):
                     with patch("os.path.isfile", return_value=True):
-                        result = _find_copilot_cli({})
+                        with patch("amplifier_module_provider_github_copilot._ensure_executable"):
+                            result = _find_copilot_cli({})
 
-                        assert result == "/usr/bin/copilot"
+                            assert result == "/usr/bin/copilot"
 
     def test_cli_not_found_returns_none(self):
         """_find_copilot_cli should return None when CLI not found."""
@@ -225,9 +234,10 @@ def test_cli_relative_path_resolved_via_which(self):
 
         with patch("os.path.isabs", return_value=False):
             with patch("shutil.which", return_value="/resolved/path/copilot"):
-                result = _find_copilot_cli({"cli_path": "copilot"})
+                with patch("amplifier_module_provider_github_copilot._ensure_executable"):
+                    result = _find_copilot_cli({"cli_path": "copilot"})
 
-                assert result == "/resolved/path/copilot"
+                    assert result == "/resolved/path/copilot"
 
     def test_cli_relative_path_not_found_in_path(self):
         """_find_copilot_cli should return None if relative path not in PATH."""

tests/test_mount_coverage.py

@@ -22,14 +22,15 @@ async def test_mount_returns_none_when_provider_creation_raises(self, mock_coord
         with patch("shutil.which", return_value="/usr/bin/copilot"):
             with patch("os.path.isfile", return_value=True):
                 with patch("os.path.isabs", return_value=True):
-                    with patch(
-                        "amplifier_module_provider_github_copilot.CopilotSdkProvider",
-                        side_effect=Exception("Init explosion"),
-                    ):
-                        cleanup = await mount(mock_coordinator, {"model": "claude-opus-4.5"})
+                    with patch("amplifier_module_provider_github_copilot._ensure_executable"):
+                        with patch(
+                            "amplifier_module_provider_github_copilot.CopilotSdkProvider",
+                            side_effect=Exception("Init explosion"),
+                        ):
+                            cleanup = await mount(mock_coordinator, {"model": "claude-opus-4.5"})
 
-                        assert cleanup is None
-                        assert "github-copilot" not in mock_coordinator.mounted_providers
+                            assert cleanup is None
+                            assert "github-copilot" not in mock_coordinator.mounted_providers
 
     @pytest.mark.asyncio
     async def test_mount_returns_none_when_coordinator_mount_raises(self, mock_coordinator):
@@ -39,9 +40,10 @@ async def test_mount_returns_none_when_coordinator_mount_raises(self, mock_coord
         with patch("shutil.which", return_value="/usr/bin/copilot"):
             with patch("os.path.isfile", return_value=True):
                 with patch("os.path.isabs", return_value=True):
-                    cleanup = await mount(mock_coordinator, {})
+                    with patch("amplifier_module_provider_github_copilot._ensure_executable"):
+                        cleanup = await mount(mock_coordinator, {})
 
-                    assert cleanup is None
+                        assert cleanup is None
 
 
 class TestFindCopilotCliEnvVar:
@@ -54,24 +56,26 @@ async def test_env_var_cli_path(self, mock_coordinator):
             with patch("shutil.which", return_value=None):
                 with patch("os.path.isfile", return_value=True):
                     with patch("os.path.isabs", return_value=True):
-                        cleanup = await mount(mock_coordinator, {})
+                        with patch("amplifier_module_provider_github_copilot._ensure_executable"):
+                            cleanup = await mount(mock_coordinator, {})
 
-                        assert cleanup is not None
-                        provider = mock_coordinator.mounted_providers.get("github-copilot")
-                        assert provider is not None
+                            assert cleanup is not None
+                            provider = mock_coordinator.mounted_providers.get("github-copilot")
+                            assert provider is not None
 
     @pytest.mark.asyncio
     async def test_config_cli_path_takes_priority_over_env(self, mock_coordinator):
         """Config cli_path should be used even when env var is set."""
         with patch.dict(os.environ, {"COPILOT_CLI_PATH": "/env/copilot"}):
             with patch("os.path.isfile", return_value=True):
                 with patch("os.path.isabs", return_value=True):
-                    cleanup = await mount(
-                        mock_coordinator,
-                        {"cli_path": "/config/copilot"},
-                    )
+                    with patch("amplifier_module_provider_github_copilot._ensure_executable"):
+                        cleanup = await mount(
+                            mock_coordinator,
+                            {"cli_path": "/config/copilot"},
+                        )
 
-                    assert cleanup is not None
+                        assert cleanup is not None
 
 
 class TestFindCopilotCliAbsolutePath:
@@ -94,12 +98,13 @@ async def test_absolute_path_exists_succeeds(self, mock_coordinator):
         """Should succeed when absolute path to CLI exists."""
         with patch("os.path.isabs", return_value=True):
             with patch("os.path.isfile", return_value=True):
-                cleanup = await mount(
-                    mock_coordinator,
-                    {"cli_path": "/usr/local/bin/copilot"},
-                )
+                with patch("amplifier_module_provider_github_copilot._ensure_executable"):
+                    cleanup = await mount(
+                        mock_coordinator,
+                        {"cli_path": "/usr/local/bin/copilot"},
+                    )
 
-                assert cleanup is not None
+                    assert cleanup is not None
 
 
 class TestFindCopilotCliNonAbsolutePath:
@@ -122,12 +127,13 @@ async def test_non_absolute_path_found_in_path(self, mock_coordinator):
         """Should resolve non-absolute CLI name through PATH."""
         with patch("os.path.isabs", return_value=False):
             with patch("shutil.which", return_value="/usr/bin/copilot"):
-                cleanup = await mount(
-                    mock_coordinator,
-                    {"cli_path": "copilot"},
-                )
+                with patch("amplifier_module_provider_github_copilot._ensure_executable"):
+                    cleanup = await mount(
+                        mock_coordinator,
+                        {"cli_path": "copilot"},
+                    )
 
-                assert cleanup is not None
+                    assert cleanup is not None
 
 
 class TestFindCopilotCliExceptionPath:
@@ -175,5 +181,6 @@ def which_side_effect(name):
             with patch("shutil.which", side_effect=which_side_effect):
                 with patch("os.path.isabs", return_value=True):
                     with patch("os.path.isfile", return_value=True):
-                        result = _find_copilot_cli({})
-                        assert result == "C:\\Program Files\\copilot\\copilot.exe"
+                        with patch("amplifier_module_provider_github_copilot._ensure_executable"):
+                            result = _find_copilot_cli({})
+                            assert result == "C:\\Program Files\\copilot\\copilot.exe"