Run the Final Integration Test

Task

Verify the complete calculator as one finished application.

Test the core workflow

Perform:

12 + 30 = 42
56 - 33 = 23
7 × 6 = 42
95 ÷ 3

Confirm the results appear correctly.

Test controls

Verify:

• Clear
• Backspace
• Decimal
• Percentage
• Sign toggle

Test keyboard input

Verify:

• numbers
• decimal
• +
• -
• *
• /
• Enter
• =
• Backspace
• Escape

Test history

Confirm:

1. completed calculations appear in history
2. newest entries appear first
3. clicking an entry restores its result
4. Clear removes all entries

Test persistence

Refresh the browser and confirm:

• history remains
• theme preference remains

Final browser check

Open the browser console and confirm there are no unexpected errors during normal use.

Then test the application from a fresh page load one final time.

Checkpoint

The calculator is complete: its core logic, controls, keyboard interaction, history, persistence, and preferences work together as one application.