diff --git a/src/composables/usePngExport.test.ts b/src/composables/usePngExport.test.ts
new file mode 100644
index 0000000..9514ac2
--- /dev/null
+++ b/src/composables/usePngExport.test.ts
@@ -0,0 +1,17 @@
+import { describe, it, expect } from 'vitest'
+import { exportFilename } from './usePngExport'
+
+describe('exportFilename', () => {
+  it('slugifies the plan title into a .png name', () => {
+    expect(exportFilename('Q3 — Checkout revamp')).toBe('macroplan-q3-checkout-revamp.png')
+  })
+
+  it('collapses runs of punctuation/space and trims edge dashes', () => {
+    expect(exportFilename('  Hello, World!!  ')).toBe('macroplan-hello-world.png')
+  })
+
+  it('falls back to a generic name when the title has no usable characters', () => {
+    expect(exportFilename('')).toBe('macroplan-plan.png')
+    expect(exportFilename('—— ··')).toBe('macroplan-plan.png')
+  })
+})