diff --git a/src/components/Editor.test.tsx b/src/components/Editor.test.tsx
new file mode 100644
index 00000000..24165354
--- /dev/null
+++ b/src/components/Editor.test.tsx
@@ -0,0 +1,220 @@
+import { render, screen, fireEvent } from '@testing-library/react'
+import { describe, it, expect, vi } from 'vitest'
+
+// Mock BlockNote components
+vi.mock('@blocknote/core', () => ({
+  BlockNoteSchema: { create: () => ({}) },
+  defaultInlineContentSpecs: {},
+  filterSuggestionItems: vi.fn(() => []),
+}))
+
+vi.mock('@blocknote/core/extensions', () => ({
+  filterSuggestionItems: vi.fn(() => []),
+}))
+
+vi.mock('@blocknote/react', () => ({
+  createReactInlineContentSpec: () => ({ render: () => null }),
+  useCreateBlockNote: () => ({
+    tryParseMarkdownToBlocks: async () => [],
+    replaceBlocks: () => {},
+    document: [],
+    insertInlineContent: () => {},
+  }),
+  SuggestionMenuController: () => null,
+}))
+
+vi.mock('@blocknote/mantine', () => ({
+  BlockNoteView: ({ children }: any) => <div data-testid="blocknote-view">{children}</div>,
+}))
+
+vi.mock('@blocknote/mantine/style.css', () => ({}))
+
+import { Editor } from './Editor'
+import type { VaultEntry } from '../types'
+
+const mockEntry: VaultEntry = {
+  path: '/vault/project/test.md',
+  filename: 'test.md',
+  title: 'Test Project',
+  isA: 'Project',
+  aliases: [],
+  belongsTo: [],
+  relatedTo: [],
+  status: 'Active',
+  owner: 'Luca',
+  cadence: null,
+  modifiedAt: 1700000000,
+  createdAt: null,
+  fileSize: 1024,
+}
+
+const mockContent = `---
+title: Test Project
+is_a: Project
+Status: Active
+---
+
+# Test Project
+
+This is a test note with some words to count.
+`
+
+const mockTab = { entry: mockEntry, content: mockContent }
+
+const defaultProps = {
+  tabs: [] as { entry: VaultEntry; content: string }[],
+  activeTabPath: null as string | null,
+  entries: [mockEntry],
+  onSwitchTab: vi.fn(),
+  onCloseTab: vi.fn(),
+  onNavigateWikilink: vi.fn(),
+  inspectorCollapsed: true,
+  onToggleInspector: vi.fn(),
+  inspectorWidth: 280,
+  onInspectorResize: vi.fn(),
+  inspectorEntry: null as VaultEntry | null,
+  inspectorContent: null as string | null,
+  allContent: {} as Record<string, string>,
+  gitHistory: [],
+  onCreateNote: vi.fn(),
+}
+
+describe('Editor', () => {
+  it('shows empty state when no tabs are open', () => {
+    render(<Editor {...defaultProps} />)
+    expect(screen.getByText('Select a note to start editing')).toBeInTheDocument()
+    expect(screen.getByText(/Cmd\+P to search/)).toBeInTheDocument()
+  })
+
+  it('renders tab bar with open tabs', () => {
+    render(
+      <Editor
+        {...defaultProps}
+        tabs={[mockTab]}
+        activeTabPath={mockEntry.path}
+      />
+    )
+    expect(screen.getAllByText('Test Project').length).toBeGreaterThan(0)
+  })
+
+  it('renders breadcrumb bar with note info', () => {
+    render(
+      <Editor
+        {...defaultProps}
+        tabs={[mockTab]}
+        activeTabPath={mockEntry.path}
+      />
+    )
+    // Breadcrumb shows type and title
+    expect(screen.getByText('Project')).toBeInTheDocument()
+    // Word count shown
+    expect(screen.getByText(/words/)).toBeInTheDocument()
+  })
+
+  it('calls onCloseTab when close button is clicked', () => {
+    const onCloseTab = vi.fn()
+    render(
+      <Editor
+        {...defaultProps}
+        tabs={[mockTab]}
+        activeTabPath={mockEntry.path}
+        onCloseTab={onCloseTab}
+      />
+    )
+    // Find the close button (X icon) in the tab
+    const closeButtons = document.querySelectorAll('button')
+    const tabCloseBtn = Array.from(closeButtons).find(btn => {
+      const svg = btn.querySelector('svg')
+      return svg && btn.closest('[class*="group"]')
+    })
+    if (tabCloseBtn) {
+      fireEvent.click(tabCloseBtn)
+      expect(onCloseTab).toHaveBeenCalledWith(mockEntry.path)
+    }
+  })
+
+  it('calls onSwitchTab when clicking a tab', () => {
+    const secondEntry: VaultEntry = {
+      ...mockEntry,
+      path: '/vault/topic/dev.md',
+      title: 'Dev Topic',
+      isA: 'Topic',
+    }
+    const onSwitchTab = vi.fn()
+    render(
+      <Editor
+        {...defaultProps}
+        tabs={[mockTab, { entry: secondEntry, content: '# Dev' }]}
+        activeTabPath={mockEntry.path}
+        onSwitchTab={onSwitchTab}
+      />
+    )
+    fireEvent.click(screen.getByText('Dev Topic'))
+    expect(onSwitchTab).toHaveBeenCalledWith(secondEntry.path)
+  })
+
+  it('renders new note button in tab bar', () => {
+    const onCreateNote = vi.fn()
+    render(
+      <Editor
+        {...defaultProps}
+        onCreateNote={onCreateNote}
+      />
+    )
+    const newNoteBtn = screen.getByTitle('New note')
+    expect(newNoteBtn).toBeInTheDocument()
+    fireEvent.click(newNoteBtn)
+    expect(onCreateNote).toHaveBeenCalled()
+  })
+
+  it('shows BlockNote editor when a tab is active', () => {
+    render(
+      <Editor
+        {...defaultProps}
+        tabs={[mockTab]}
+        activeTabPath={mockEntry.path}
+      />
+    )
+    expect(screen.getByTestId('blocknote-view')).toBeInTheDocument()
+  })
+
+  it('shows modified indicator when file is modified', () => {
+    render(
+      <Editor
+        {...defaultProps}
+        tabs={[mockTab]}
+        activeTabPath={mockEntry.path}
+        isModified={() => true}
+      />
+    )
+    // Modified indicator shows "M" in the breadcrumb
+    expect(screen.getByText('M')).toBeInTheDocument()
+  })
+
+  it('renders diff toggle button when file is modified', () => {
+    render(
+      <Editor
+        {...defaultProps}
+        tabs={[mockTab]}
+        activeTabPath={mockEntry.path}
+        isModified={() => true}
+        onLoadDiff={async () => '+ added line'}
+      />
+    )
+    const diffBtn = screen.getByTitle('Show diff')
+    expect(diffBtn).toBeInTheDocument()
+  })
+
+  it('includes inspector panel', () => {
+    render(
+      <Editor
+        {...defaultProps}
+        inspectorCollapsed={false}
+        inspectorEntry={mockEntry}
+        inspectorContent={mockContent}
+      />
+    )
+    // Inspector renders "Properties" header
+    expect(screen.getAllByText('Properties').length).toBeGreaterThan(0)
+  })
+})