test: add project name display tests

- Add comprehensive tests for getProjectDisplayName function
- Test various path structures including worktrees, nested projects, and edge cases
- Include regression tests for the reported bug cases
- Create separate utility file for better testability

Fixes session stats display where wrong fragments were shown
Related to: #348 (quota display), #103 (context display)

ui/tests/unit/components/analytics/project-name-display.test.ts

@@ -0,0 +1,127 @@
+/**
+ * Project Name Display Tests
+ * Unit tests for getProjectDisplayName function
+ */
+
+import { describe, it, expect } from 'vitest';
+
+// Import the function from the utility
+import { getProjectDisplayName } from '../../../../../src/components/analytics/project-name-utils';
+
+describe('getProjectDisplayName', () => {
+  describe('Simple project paths', () => {
+    it('returns the leaf folder name for simple paths', () => {
+      expect(getProjectDisplayName('/home/user/projects/my-app')).toBe('my-app');
+      expect(getProjectDisplayName('/Users/joe/Developer/share-pi')).toBe('share-pi');
+      expect(getProjectDisplayName('/var/www/html')).toBe('html');
+    });
+
+    it('handles paths without leading/trailing slashes', () => {
+      expect(getProjectDisplayName('home/user/projects/my-app')).toBe('my-app');
+      expect(getProjectDisplayName('Users/joe/Developer/share-pi')).toBe('share-pi');
+    });
+  });
+
+  describe('Complex project paths', () => {
+    it('returns leaf folder for worktree paths', () => {
+      expect(getProjectDisplayName('/Users/joe/Developer/ExaDev/Clients/Architect/repositories/architect/worktrees/2026-01-08')).toBe('2026-01-08');
+      expect(getProjectDisplayName('/home/user/workspaces/repo-name/worktrees/feature-branch')).toBe('feature-branch');
+      expect(getProjectDisplayName('/project/repo/worktrees/v2.0')).toBe('v2.0');
+    });
+
+    it('handles nested paths', () => {
+      expect(getProjectDisplayName('/home/user/projects/web-dashboard/src/components')).toBe('components');
+      expect(getProjectDisplayName('/opt/apps/my-app/lib/utils')).toBe('utils');
+    });
+  });
+
+  describe('Edge cases', () => {
+    it('handles empty string', () => {
+      expect(getProjectDisplayName('')).toBe('');
+    });
+
+    it('handles only slashes', () => {
+      expect(getProjectDisplayName('///')).toBe('');
+      expect(getProjectDisplayName('/')).toBe('');
+    });
+
+    it('handles single segment paths', () => {
+      expect(getProjectDisplayName('my-app')).toBe('my-app');
+      expect(getProjectDisplayName('project')).toBe('project');
+    });
+
+    it('handles paths with trailing slash', () => {
+      expect(getProjectDisplayName('/home/user/projects/my-app/')).toBe('my-app');
+      expect(getProjectDisplayName('/Users/joe/Developer/share-pi/')).toBe('share-pi');
+    });
+
+    it('handles paths with leading slash only', () => {
+      expect(getProjectDisplayName('/my-app')).toBe('my-app');
+      expect(getProjectDisplayName('/project')).toBe('project');
+    });
+  });
+
+  describe('Real-world examples from the bug report', () => {
+    it('displays correct project name for share-pi project', () => {
+      // Before fix: would show "pi"
+      // After fix: should show "share-pi"
+      const path = '/Users/joe/Developer/share-pi';
+      expect(getProjectDisplayName(path)).toBe('share-pi');
+    });
+
+    it('displays correct project name for worktree project', () => {
+      // Before fix: would show "08"
+      // After fix: should show "2026-01-08"
+      const path = '/Users/joe/Developer/ExaDev/Clients/Architect/repositories/architect.worktrees/2026-01-08';
+      expect(getProjectDisplayName(path)).toBe('2026-01-08');
+    });
+
+    it('displays correct project name for nested project', () => {
+      // Example: a project in a subdirectory
+      const path = '/home/user/dev/company/projects/web-app';
+      expect(getProjectDisplayName(path)).toBe('web-app');
+    });
+
+    it('displays correct project name for repo with worktrees', () => {
+      // Example: main repository
+      const path = '/Users/joe/Developer/my-repo';
+      expect(getProjectDisplayName(path)).toBe('my-repo');
+    });
+
+    it('displays correct project name for feature branch worktree', () => {
+      // Example: feature branch worktree
+      const path = '/Users/joe/Developer/my-repo/.git/worktrees/feature-x';
+      expect(getProjectDisplayName(path)).toBe('feature-x');
+    });
+  });
+
+  describe('Regression tests', () => {
+    it('does not return empty string for valid paths', () => {
+      const testCases = [
+        '/project',
+        '/home/user/app',
+        '/var/log/nginx',
+        '/tmp/test-file',
+      ];
+
+      testCases.forEach(path => {
+        const result = getProjectDisplayName(path);
+        expect(result).not.toBe('');
+        expect(result).not.toBeUndefined();
+        expect(result).not.toBeNull();
+      });
+    });
+
+    it('handles paths with special characters', () => {
+      expect(getProjectDisplayName('/home/user/my-project_v2')).toBe('my-project_v2');
+      expect(getProjectDisplayName('/home/user/project-with-dashes')).toBe('project-with-dashes');
+      expect(getProjectDisplayName('/home/user/project.with.dots')).toBe('project.with.dots');
+    });
+
+    it('handles numeric paths correctly', () => {
+      expect(getProjectDisplayName('/home/user/project123')).toBe('project123');
+      expect(getProjectDisplayName('/home/user/123project')).toBe('123project');
+      expect(getProjectDisplayName('/home/user/v1.2.3')).toBe('v1.2.3');
+    });
+  });
+});