diff --git a/frontend/src/__tests__/dms/BulkActions.test.tsx b/frontend/src/__tests__/dms/BulkActions.test.tsx
new file mode 100644
index 0000000..81a83f7
--- /dev/null
+++ b/frontend/src/__tests__/dms/BulkActions.test.tsx
@@ -0,0 +1,64 @@
+import React from 'react';
+import { describe, it, expect, vi } from 'vitest';
+import { render, screen, fireEvent } from '@testing-library/react';
+import { BulkActions } from '@/components/dms/BulkActions';
+import type { DmsFolder } from '@/api/dms';
+
+vi.mock('@/api/dms', () => ({
+  bulkMoveFiles: vi.fn().mockResolvedValue(undefined),
+  bulkDeleteFiles: vi.fn().mockResolvedValue(undefined),
+}));
+
+vi.mock('@/components/ui/Toast', () => ({
+  useToast: () => ({ success: vi.fn(), error: vi.fn(), info: vi.fn() }),
+}));
+
+const mockFolders: DmsFolder[] = [
+  { id: 'folder1', name: 'Documents', parent_id: null, created_by: 'user1', created_at: '2024-01-01T00:00:00Z' },
+  { id: 'folder2', name: 'Images', parent_id: null, created_by: 'user1', created_at: '2024-01-01T00:00:00Z' },
+];
+
+const defaultProps = {
+  selectedFileIds: new Set(['f1', 'f2', 'f3']),
+  folders: mockFolders,
+  onClear: vi.fn(),
+  onActionComplete: vi.fn(),
+};
+
+describe('BulkActions', () => {
+  it('renders bulk actions bar when files are selected', () => {
+    render(<BulkActions {...defaultProps} />);
+    expect(screen.getByTestId('bulk-actions-bar')).toBeInTheDocument();
+  });
+
+  it('does not render when no files selected', () => {
+    render(<BulkActions {...defaultProps} selectedFileIds={new Set()} />);
+    expect(screen.queryByTestId('bulk-actions-bar')).not.toBeInTheDocument();
+  });
+
+  it('renders selected file count', () => {
+    render(<BulkActions {...defaultProps} />);
+    expect(screen.getByText(/3/)).toBeInTheDocument();
+  });
+
+  it('renders move button', () => {
+    render(<BulkActions {...defaultProps} />);
+    expect(screen.getByText(/move|verschieben/i)).toBeInTheDocument();
+  });
+
+  it('renders delete button', () => {
+    render(<BulkActions {...defaultProps} />);
+    expect(screen.getByText(/delete|löschen/i)).toBeInTheDocument();
+  });
+
+  it('renders cancel/clear button', () => {
+    render(<BulkActions {...defaultProps} />);
+    expect(screen.getByText(/cancel|abbrechen/i)).toBeInTheDocument();
+  });
+
+  it('calls onClear when cancel button clicked', () => {
+    render(<BulkActions {...defaultProps} />);
+    fireEvent.click(screen.getByText(/cancel|abbrechen/i));
+    expect(defaultProps.onClear).toHaveBeenCalled();
+  });
+});
diff --git a/frontend/src/__tests__/dms/FileDetails.test.tsx b/frontend/src/__tests__/dms/FileDetails.test.tsx
new file mode 100644
index 0000000..4780325
--- /dev/null
+++ b/frontend/src/__tests__/dms/FileDetails.test.tsx
@@ -0,0 +1,78 @@
+import React from 'react';
+import { describe, it, expect, vi } from 'vitest';
+import { render, screen, fireEvent } from '@testing-library/react';
+import { FileDetails } from '@/components/dms/FileDetails';
+import type { DmsFile } from '@/api/dms';
+
+const mockFile: DmsFile = {
+  id: 'f1',
+  folder_id: 'folder1',
+  name: 'document.pdf',
+  mime_type: 'application/pdf',
+  size_bytes: 1024,
+  storage_path: '/path/f1',
+  deleted_at: null,
+  uploaded_by: 'user1',
+  created_at: '2024-01-01T10:00:00Z',
+  updated_at: '2024-01-02T12:00:00Z',
+  access_level: 'read',
+};
+
+const defaultProps = {
+  file: mockFile,
+  onPreview: vi.fn(),
+  onShare: vi.fn(),
+  onDelete: vi.fn(),
+  onClose: vi.fn(),
+};
+
+describe('FileDetails', () => {
+  it('renders file details container', () => {
+    render(<FileDetails {...defaultProps} />);
+    expect(screen.getByTestId('file-details')).toBeInTheDocument();
+  });
+
+  it('renders file name in header', () => {
+    render(<FileDetails {...defaultProps} />);
+    expect(screen.getAllByText('document.pdf').length).toBeGreaterThan(0);
+  });
+
+  it('renders empty state when no file selected', () => {
+    render(<FileDetails {...defaultProps} file={null} />);
+    expect(screen.getByTestId('file-details-empty')).toBeInTheDocument();
+  });
+
+  it('renders close button', () => {
+    render(<FileDetails {...defaultProps} />);
+    expect(screen.getByLabelText(/close|schließen/i)).toBeInTheDocument();
+  });
+
+  it('calls onClose when close button clicked', () => {
+    render(<FileDetails {...defaultProps} />);
+    fireEvent.click(screen.getByLabelText(/close|schließen/i));
+    expect(defaultProps.onClose).toHaveBeenCalled();
+  });
+
+  it('renders preview button', () => {
+    render(<FileDetails {...defaultProps} />);
+    const previewBtn = screen.getByText(/preview|vorschau/i);
+    expect(previewBtn).toBeInTheDocument();
+  });
+
+  it('calls onPreview when preview button clicked', () => {
+    render(<FileDetails {...defaultProps} />);
+    fireEvent.click(screen.getByText(/preview|vorschau/i));
+    expect(defaultProps.onPreview).toHaveBeenCalledWith(mockFile);
+  });
+
+  it('renders delete button', () => {
+    render(<FileDetails {...defaultProps} />);
+    expect(screen.getByText(/delete|löschen/i)).toBeInTheDocument();
+  });
+
+  it('calls onDelete when delete button clicked', () => {
+    render(<FileDetails {...defaultProps} />);
+    fireEvent.click(screen.getByText(/delete|löschen/i));
+    expect(defaultProps.onDelete).toHaveBeenCalledWith(mockFile);
+  });
+});
diff --git a/frontend/src/__tests__/dms/FileExplorer.test.tsx b/frontend/src/__tests__/dms/FileExplorer.test.tsx
new file mode 100644
index 0000000..0c3e43d
--- /dev/null
+++ b/frontend/src/__tests__/dms/FileExplorer.test.tsx
@@ -0,0 +1,71 @@
+import React from 'react';
+import { describe, it, expect, vi } from 'vitest';
+import { render, screen, fireEvent } from '@testing-library/react';
+import { FileExplorer } from '@/components/dms/FileExplorer';
+import type { DmsFile } from '@/api/dms';
+
+const mockFiles: DmsFile[] = [
+  { id: 'f1', folder_id: null, name: 'document.pdf', mime_type: 'application/pdf', size_bytes: 1024, storage_path: '/path/f1', deleted_at: null, uploaded_by: 'user1', created_at: '2024-01-01T00:00:00Z', updated_at: '2024-01-02T00:00:00Z' },
+  { id: 'f2', folder_id: null, name: 'image.png', mime_type: 'image/png', size_bytes: 2048, storage_path: '/path/f2', deleted_at: null, uploaded_by: 'user2', created_at: '2024-01-01T00:00:00Z', updated_at: '2024-01-03T00:00:00Z' },
+];
+
+const defaultProps = {
+  files: mockFiles,
+  selectedFileIds: new Set<string>(),
+  selectedFile: null,
+  viewMode: 'list' as const,
+  onToggleSelect: vi.fn(),
+  onFileClick: vi.fn(),
+  onFileDoubleClick: vi.fn(),
+  onFileShare: vi.fn(),
+  onFileDelete: vi.fn(),
+  onFilePreview: vi.fn(),
+  sortBy: 'name' as const,
+  sortOrder: 'asc' as const,
+  onSortChange: vi.fn(),
+};
+
+describe('FileExplorer', () => {
+  it('renders file list in list view', () => {
+    render(<FileExplorer {...defaultProps} />);
+    expect(screen.getByTestId('file-explorer-list')).toBeInTheDocument();
+  });
+
+  it('renders file rows for each file', () => {
+    render(<FileExplorer {...defaultProps} />);
+    expect(screen.getByTestId('file-row-f1')).toBeInTheDocument();
+    expect(screen.getByTestId('file-row-f2')).toBeInTheDocument();
+  });
+
+  it('renders file names', () => {
+    render(<FileExplorer {...defaultProps} />);
+    expect(screen.getByText('document.pdf')).toBeInTheDocument();
+    expect(screen.getByText('image.png')).toBeInTheDocument();
+  });
+
+  it('shows loading state', () => {
+    render(<FileExplorer {...defaultProps} loading={true} />);
+    expect(screen.getByTestId('file-explorer-loading')).toBeInTheDocument();
+  });
+
+  it('shows empty state when no files', () => {
+    render(<FileExplorer {...defaultProps} files={[]} />);
+    expect(screen.getByTestId('file-explorer-empty')).toBeInTheDocument();
+  });
+
+  it('calls onFileClick when file row clicked', () => {
+    render(<FileExplorer {...defaultProps} />);
+    fireEvent.click(screen.getByTestId('file-row-f1'));
+    expect(defaultProps.onFileClick).toHaveBeenCalledWith(mockFiles[0]);
+  });
+
+  it('renders table view when viewMode is table', () => {
+    render(<FileExplorer {...defaultProps} viewMode="table" />);
+    expect(screen.getByTestId('file-explorer-table')).toBeInTheDocument();
+  });
+
+  it('renders icons view when viewMode is icons-md', () => {
+    render(<FileExplorer {...defaultProps} viewMode="icons-md" />);
+    expect(screen.getByTestId('file-explorer-icons-md')).toBeInTheDocument();
+  });
+});
diff --git a/frontend/src/__tests__/dms/FileGrid.test.tsx b/frontend/src/__tests__/dms/FileGrid.test.tsx
new file mode 100644
index 0000000..fc8970f
--- /dev/null
+++ b/frontend/src/__tests__/dms/FileGrid.test.tsx
@@ -0,0 +1,61 @@
+import React from 'react';
+import { describe, it, expect, vi } from 'vitest';
+import { render, screen, fireEvent } from '@testing-library/react';
+import { FileGrid } from '@/components/dms/FileGrid';
+import type { DmsFile } from '@/api/dms';
+
+const mockFiles: DmsFile[] = [
+  { id: 'f1', folder_id: null, name: 'report.pdf', mime_type: 'application/pdf', size_bytes: 1024, storage_path: '/path/f1', deleted_at: null, uploaded_by: 'user1', created_at: '2024-01-01T00:00:00Z' },
+  { id: 'f2', folder_id: null, name: 'photo.jpg', mime_type: 'image/jpeg', size_bytes: 4096, storage_path: '/path/f2', deleted_at: null, uploaded_by: 'user2', created_at: '2024-01-01T00:00:00Z' },
+];
+
+const defaultProps = {
+  files: mockFiles,
+  selectedFileIds: new Set<string>(),
+  onToggleSelect: vi.fn(),
+  onFileClick: vi.fn(),
+  onFileShare: vi.fn(),
+  onFileDelete: vi.fn(),
+  onFilePreview: vi.fn(),
+};
+
+describe('FileGrid', () => {
+  it('renders file grid container', () => {
+    render(<FileGrid {...defaultProps} />);
+    expect(screen.getByTestId('file-grid')).toBeInTheDocument();
+  });
+
+  it('renders file cards for each file', () => {
+    render(<FileGrid {...defaultProps} />);
+    expect(screen.getByTestId('file-card-f1')).toBeInTheDocument();
+    expect(screen.getByTestId('file-card-f2')).toBeInTheDocument();
+  });
+
+  it('renders file names in cards', () => {
+    render(<FileGrid {...defaultProps} />);
+    expect(screen.getByText('report.pdf')).toBeInTheDocument();
+    expect(screen.getByText('photo.jpg')).toBeInTheDocument();
+  });
+
+  it('shows loading state', () => {
+    render(<FileGrid {...defaultProps} loading={true} />);
+    expect(screen.getByTestId('file-grid-loading')).toBeInTheDocument();
+  });
+
+  it('shows empty state when no files', () => {
+    render(<FileGrid {...defaultProps} files={[]} />);
+    expect(screen.getByTestId('file-grid-empty')).toBeInTheDocument();
+  });
+
+  it('calls onFileClick when file card clicked', () => {
+    render(<FileGrid {...defaultProps} />);
+    fireEvent.click(screen.getByTestId('file-card-f1'));
+    expect(defaultProps.onFileClick).toHaveBeenCalledWith(mockFiles[0]);
+  });
+
+  it('renders checkboxes for file selection', () => {
+    render(<FileGrid {...defaultProps} />);
+    const checkboxes = screen.getAllByRole('checkbox');
+    expect(checkboxes.length).toBeGreaterThanOrEqual(2);
+  });
+});
diff --git a/frontend/src/__tests__/dms/SourceTree.test.tsx b/frontend/src/__tests__/dms/SourceTree.test.tsx
new file mode 100644
index 0000000..995dd32
--- /dev/null
+++ b/frontend/src/__tests__/dms/SourceTree.test.tsx
@@ -0,0 +1,59 @@
+import React from 'react';
+import { describe, it, expect, vi } from 'vitest';
+import { render, screen, fireEvent } from '@testing-library/react';
+import { SourceTree } from '@/components/dms/SourceTree';
+import type { DmsFolder, DmsFile } from '@/api/dms';
+
+const mockFolders: DmsFolder[] = [
+  { id: 'folder1', name: 'Documents', parent_id: null, created_by: 'user1', created_at: '2024-01-01T00:00:00Z', updated_at: '2024-01-01T00:00:00Z', file_count: 5 },
+  { id: 'folder2', name: 'Images', parent_id: null, created_by: 'user1', created_at: '2024-01-01T00:00:00Z', updated_at: '2024-01-01T00:00:00Z', file_count: 3 },
+];
+
+const mockSharedFiles: DmsFile[] = [
+  { id: 'sf1', folder_id: null, name: 'shared.doc', mime_type: 'application/msword', size_bytes: 512, storage_path: '/path/sf1', deleted_at: null, uploaded_by: 'other', created_at: '2024-01-01T00:00:00Z' },
+];
+
+const defaultProps = {
+  folders: mockFolders,
+  sharedFiles: mockSharedFiles,
+  selectedFolderId: null,
+  selectedSource: null as string | null,
+  onSelectFolder: vi.fn(),
+  onSelectSource: vi.fn(),
+  onDropFiles: vi.fn(),
+  onDropFolder: vi.fn(),
+};
+
+describe('SourceTree', () => {
+  it('renders source tree container', () => {
+    render(<SourceTree {...defaultProps} />);
+    expect(screen.getByTestId('source-tree')).toBeInTheDocument();
+  });
+
+  it('renders folder names', () => {
+    render(<SourceTree {...defaultProps} />);
+    expect(screen.getByText('Documents')).toBeInTheDocument();
+    expect(screen.getByText('Images')).toBeInTheDocument();
+  });
+
+  it('shows loading state', () => {
+    render(<SourceTree {...defaultProps} loading={true} />);
+    expect(screen.getByTestId('source-tree-loading')).toBeInTheDocument();
+  });
+
+  it('calls onSelectFolder when folder clicked', () => {
+    render(<SourceTree {...defaultProps} />);
+    fireEvent.click(screen.getByText('Documents'));
+    expect(defaultProps.onSelectFolder).toHaveBeenCalled();
+  });
+
+  it('calls onSelectSource when source clicked', () => {
+    render(<SourceTree {...defaultProps} />);
+    // Click on "All Files" entry which calls onSelectSource('local')
+    const allFilesEntry = screen.getByText(/all files|alle dateien/i);
+    if (allFilesEntry) {
+      fireEvent.click(allFilesEntry);
+      expect(defaultProps.onSelectSource).toHaveBeenCalled();
+    }
+  });
+});