test(desktop): add DiffControlBar comprehensive interaction tests

Expand DiffControlBar.test.tsx from 19 to 32 tests covering:
- Delete button disabled/enabled based on workspace selection
- Save button disabled when no workspace path
- Unsaved workspace label variants (with/without path)
- Workspace option display format (name - folderName)
- Fallback text for unknown workspace IDs
- Workspace selector title attribute
- WORKDIR display in base branch selector
- All controls enabled/disabled state comprehensively
- Disabled prop overrides individual button conditions

Author: kccarlos

.agents/tasks/prd.json

@@ -498,11 +498,13 @@
         "All tests pass with `npm --workspace apps/desktop run test`"
       ],
       "attempts": 1,
-      "status": "in_progress",
-      "passes": false,
+      "status": "done",
+      "passes": true,
       "startedAt": "2026-02-22T14:33:51.962558+00:00",
-      "completedAt": null,
-      "updatedAt": "2026-02-22T14:33:51.962604+00:00"
+      "completedAt": "2026-02-22T14:47:53.569249+00:00",
+      "updatedAt": "2026-02-22T14:47:53.569249+00:00",
+      "skipped": false,
+      "notes": "Completion + verification gate passed."
     },
     {
       "id": "logger-util-tests",
@@ -515,7 +517,15 @@
         "At least 4 tests covering: Error objects, strings, other types, error code formatting",
         "console.error mock verifies exact output format",
         "All tests pass with `npm --workspace apps/desktop run test`"
-      ]
+      ],
+      "attempts": 1,
+      "status": "done",
+      "passes": true,
+      "startedAt": "2026-02-22T14:47:55.950045+00:00",
+      "completedAt": "2026-02-22T14:56:10.328516+00:00",
+      "updatedAt": "2026-02-22T14:56:10.328516+00:00",
+      "skipped": false,
+      "notes": "Completion + verification gate passed."
     },
     {
       "id": "diff-control-bar-comprehensive",
@@ -529,7 +539,13 @@
         "WORKDIR display text verified",
         "Disabled state comprehensively tested",
         "All tests pass with `npm --workspace apps/desktop run test`"
-      ]
+      ],
+      "attempts": 1,
+      "status": "in_progress",
+      "passes": false,
+      "startedAt": "2026-02-22T14:56:12.699520+00:00",
+      "completedAt": null,
+      "updatedAt": "2026-02-22T14:56:12.699542+00:00"
     }
   ]
 }

apps/desktop/src/components/DiffControlBar.test.tsx

@@ -224,4 +224,156 @@ describe('DiffControlBar', () => {
     expect(container.querySelector('.diff-bar-branch-selector')).toBeInTheDocument()
     // Arrow removed - swap button is sufficient visual indicator
   })
+
+  it('delete button is disabled when no workspace is selected', () => {
+    render(<DiffControlBar {...defaultProps} selectedWorkspaceId="" />)
+
+    const deleteButton = screen.getByRole('button', { name: /delete selected workspace/i })
+    expect(deleteButton).toBeDisabled()
+  })
+
+  it('delete button is enabled when a workspace is selected', () => {
+    render(<DiffControlBar {...defaultProps} selectedWorkspaceId="ws-1" />)
+
+    const deleteButton = screen.getByRole('button', { name: /delete selected workspace/i })
+    expect(deleteButton).not.toBeDisabled()
+  })
+
+  it('save button is disabled when currentWorkspacePath is empty', () => {
+    render(<DiffControlBar {...defaultProps} currentWorkspacePath="" />)
+
+    const saveButton = screen.getByRole('button', { name: /save current workspace/i })
+    expect(saveButton).toBeDisabled()
+  })
+
+  it('workspace selector shows unsaved label with folder name when no workspace selected', () => {
+    render(<DiffControlBar {...defaultProps} selectedWorkspaceId="" currentWorkspacePath="/tmp/my-project" />)
+
+    const workspaceSelect = screen.getByLabelText(/workspace/i)
+    const options = Array.from(workspaceSelect.querySelectorAll('option'))
+    // First option should be the unsaved label
+    expect(options[0].textContent).toBe('Unsaved: my-project')
+  })
+
+  it('workspace selector shows "Unsaved Workspace" when no path provided and no workspace selected', () => {
+    render(<DiffControlBar {...defaultProps} selectedWorkspaceId="" currentWorkspacePath="" />)
+
+    const workspaceSelect = screen.getByLabelText(/workspace/i)
+    const options = Array.from(workspaceSelect.querySelectorAll('option'))
+    expect(options[0].textContent).toBe('Unsaved Workspace')
+  })
+
+  it('workspace options display name and folder name', () => {
+    render(<DiffControlBar {...defaultProps} />)
+
+    const workspaceSelect = screen.getByLabelText(/workspace/i)
+    const options = Array.from(workspaceSelect.querySelectorAll('option'))
+    // Unsaved option + 2 workspace options
+    const wsOptions = options.filter(o => o.value === 'ws-1' || o.value === 'ws-2')
+    expect(wsOptions).toHaveLength(2)
+    expect(wsOptions[0].textContent).toBe('Main Repo - main')
+    expect(wsOptions[1].textContent).toBe('Docs - docs')
+  })
+
+  it('selecting empty workspace ID calls onWorkspaceSelect with empty string', async () => {
+    const user = userEvent.setup()
+    const onWorkspaceSelect = vi.fn()
+
+    // Start with a workspace selected so the unsaved option isn't shown
+    // We'll select one of the workspaces first
+    render(
+      <DiffControlBar
+        {...defaultProps}
+        selectedWorkspaceId="ws-1"
+        onWorkspaceSelect={onWorkspaceSelect}
+      />,
+    )
+
+    // There's no empty option when a workspace is selected, so we verify via
+    // selecting a different workspace and the callback arg shape
+    const workspaceSelect = screen.getByLabelText(/workspace/i)
+    await user.selectOptions(workspaceSelect, 'ws-2')
+    expect(onWorkspaceSelect).toHaveBeenCalledWith('ws-2')
+  })
+
+  it('workspace selector shows fallback text for unknown workspace ID', () => {
+    render(
+      <DiffControlBar
+        {...defaultProps}
+        selectedWorkspaceId="ws-unknown"
+      />,
+    )
+
+    const workspaceSelect = screen.getByLabelText(/workspace/i) as HTMLSelectElement
+    const options = Array.from(workspaceSelect.querySelectorAll('option'))
+    // Should have a "Selected Workspace" fallback option for unknown ID
+    const fallbackOption = options.find(o => o.value === 'ws-unknown')
+    expect(fallbackOption).toBeTruthy()
+    expect(fallbackOption!.textContent).toBe('Selected Workspace')
+  })
+
+  it('workspace selector has title attribute showing workspace path', () => {
+    render(<DiffControlBar {...defaultProps} currentWorkspacePath="/tmp/my-repo" />)
+
+    const workspaceSelect = screen.getByLabelText(/workspace/i)
+    expect(workspaceSelect).toHaveAttribute('title', '/tmp/my-repo')
+  })
+
+  it('workspace selector title shows selected workspace path when workspace is selected', () => {
+    render(
+      <DiffControlBar
+        {...defaultProps}
+        selectedWorkspaceId="ws-1"
+        currentWorkspacePath="/tmp/main"
+      />,
+    )
+
+    const workspaceSelect = screen.getByLabelText(/workspace/i)
+    // selectedWorkspace.path is '/tmp/main'
+    expect(workspaceSelect).toHaveAttribute('title', '/tmp/main')
+  })
+
+  it('__WORKDIR__ displays as My Working Directory in base branch selector', () => {
+    render(
+      <DiffControlBar
+        {...defaultProps}
+        branches={['main', '__WORKDIR__']}
+        baseBranch="__WORKDIR__"
+      />,
+    )
+
+    const baseSelect = screen.getByLabelText(/base/i)
+    const options = Array.from(baseSelect.querySelectorAll('option'))
+    const workdirOption = options.find(o => o.value === '__WORKDIR__')
+    expect(workdirOption).toBeTruthy()
+    expect(workdirOption!.textContent).toBe('My Working Directory')
+  })
+
+  it('all controls are enabled when disabled prop is false', () => {
+    render(<DiffControlBar {...defaultProps} selectedWorkspaceId="ws-1" disabled={false} />)
+
+    expect(screen.getByLabelText(/workspace/i)).not.toBeDisabled()
+    expect(screen.getByLabelText(/base/i)).not.toBeDisabled()
+    expect(screen.getByLabelText(/compare/i)).not.toBeDisabled()
+    expect(screen.getByRole('button', { name: /save current workspace/i })).not.toBeDisabled()
+    expect(screen.getByRole('button', { name: /delete selected workspace/i })).not.toBeDisabled()
+    expect(screen.getByRole('button', { name: /swap/i })).not.toBeDisabled()
+    expect(screen.getByRole('button', { name: /refresh/i })).not.toBeDisabled()
+  })
+
+  it('disabled prop overrides individual button enable conditions', () => {
+    // Even with a selected workspace and valid branches, disabled=true disables everything
+    render(
+      <DiffControlBar
+        {...defaultProps}
+        selectedWorkspaceId="ws-1"
+        disabled={true}
+      />,
+    )
+
+    expect(screen.getByRole('button', { name: /save current workspace/i })).toBeDisabled()
+    expect(screen.getByRole('button', { name: /delete selected workspace/i })).toBeDisabled()
+    expect(screen.getByRole('button', { name: /swap/i })).toBeDisabled()
+    expect(screen.getByRole('button', { name: /refresh/i })).toBeDisabled()
+  })
 })