diff --git a/tests/treeDataProvider.test.ts b/tests/treeDataProvider.test.ts
new file mode 100644
index 0000000..9273ee0
--- /dev/null
+++ b/tests/treeDataProvider.test.ts
@@ -0,0 +1,67 @@
+import { describe, expect, it } from 'vitest';
+import { VerificationReport } from '../src/types';
+import { ProofCodeTreeDataProvider } from '../src/ui/treeDataProvider';
+
+describe('ProofCodeTreeDataProvider', () => {
+  it('should show run message when no report is set', async () => {
+    const provider = new ProofCodeTreeDataProvider();
+    const children = await provider.getChildren();
+    expect(children).toHaveLength(1);
+    expect(children[0].label).toContain('Run "ProofCode: Verify Current Changes"');
+  });
+
+  it('should render root categories when a report is loaded', async () => {
+    const provider = new ProofCodeTreeDataProvider();
+    const mockReport: VerificationReport = {
+      timestamp: new Date().toISOString(),
+      repoRoot: '/workspace',
+      branch: 'working',
+      score: { total: 85, deductions: [] },
+      verdict: 'READY_TO_SHIP',
+      summary: {
+        filesChanged: 3,
+        linesAdded: 50,
+        linesDeleted: 10,
+        symbolsAffected: 4,
+        apiRoutesAffected: 1,
+        testsAdded: 1,
+        testsAffected: 1,
+        highRiskCount: 0,
+        mediumRiskCount: 0,
+        lowRiskCount: 0
+      },
+      impact: {
+        changedFiles: ['/workspace/src/app.ts'],
+        changedSymbols: [],
+        affectedFiles: [],
+        affectedCallers: [],
+        affectedRoutes: [],
+        totalCallersCount: 0,
+        untestedCallersCount: 0
+      },
+      risks: [],
+      rules: [],
+      checks: {
+        typescript: { name: 'TypeScript', status: 'PASS' },
+        eslint: { name: 'ESLint', status: 'PASS' },
+        unitTests: { name: 'Unit Tests', status: 'PASS' },
+        build: { name: 'Build', status: 'PASS' }
+      }
+    };
+
+    provider.setReport(mockReport);
+    const roots = await provider.getChildren();
+    expect(roots).toHaveLength(6);
+    expect(roots[0].label).toContain('Verification Score: 85%');
+    expect(roots[1].label).toContain('Changed Files (3)');
+    expect(roots[2].label).toContain('Impact');
+    expect(roots[3].label).toContain('Risks & Evidence (0)');
+    expect(roots[4].label).toContain('Project Rules');
+    expect(roots[5].label).toContain('Checks & Tests');
+
+    // Get children of Changed Files
+    const fileChildren = await provider.getChildren(roots[1]);
+    expect(fileChildren).toHaveLength(1);
+    expect(fileChildren[0].label).toBe('app.ts');
+  });
+});