Real-World Combined Testing Scenarios

Real users don't experience your app in ideal conditions. They're on a phone, on a train, with spotty 3G, in a timezone 12 hours from your server. The most valuable tests combine multiple conditions to simulate these real scenarios.

Certyn's tools are designed to work together. Here are battle-tested combinations that catch bugs individual tools miss.

Mobile User on a Slow Network

Tools: simulate_device + simulate_network

A user in a rural area opens your app on their phone over a slow connection. This is one of the most common real-world scenarios and the most frequently skipped in testing.

"Emulate an iPhone 12 and simulate a 3G network. Navigate to the product listing page. Verify all images load, the layout doesn't break, and the page is usable within 5 seconds."

What to check:

• Do images have proper loading states (placeholders, skeletons)?
• Does the layout stay stable as images load (no content shifting)?
• Are touch targets large enough on the small screen?
• Does the page remain interactive during loading?

International E-Commerce Customer

Tools: emulate_location + emulate_timezone + simulate_device

A customer in Tokyo is browsing your store on their phone. Prices, dates, and shipping information all need to be correct for their region.

"Set location to Tokyo (35.6762, 139.6503), set timezone to Asia/Tokyo, and emulate a Pixel 7. Navigate to the product page and verify: prices show in the correct currency, delivery dates account for the timezone, and the mobile layout is correct."

What to check:

• Currency display and conversion
• Delivery date calculations across the date line
• Locale-appropriate date and time formatting
• Mobile layout with potentially longer translated strings

Accessibility on Mobile

Tools: simulate_device + get_accessibility_tree

Mobile accessibility is often worse than desktop. Smaller touch targets, different layouts, and hidden navigation can all break screen reader compatibility.

"Emulate an iPad and get the accessibility tree of the main navigation. Verify all menu items have proper labels, the hamburger menu has the correct ARIA attributes, and the heading hierarchy is maintained."

What to check:

• Mobile navigation has proper ARIA roles (navigation, menu, menuitem)
• Hamburger/drawer menu has aria-expanded state
• Touch targets meet minimum 44x44px size
• Heading hierarchy doesn't break when layout changes

Dark Mode on Multiple Devices

Tools: emulate_media + simulate_device

Dark mode rendering can vary across device sizes. A color that's readable on desktop might have insufficient contrast on a small mobile screen.

"Enable dark mode, then test the settings page on iPhone SE, iPad, and desktop. Check that all text is readable, form inputs have visible borders, and no elements disappear against the dark background."

What to check:

• Text contrast meets WCAG AA (4.5:1 for normal text)
• Form field borders are visible
• Placeholder text is readable
• Focus indicators are visible in dark mode
• Images and icons adapt (or at least remain visible)

Performance Under Pressure

Tools: simulate_network + get_performance_metrics

Test how your app performs when the network is slow — the condition where performance matters most.

"Simulate a slow 3G network. Navigate to the dashboard. Get performance metrics. Then interact with the data table: sort, filter, and paginate. Get metrics again. Compare the before and after."

What to check:

• FirstContentfulPaint under 5s on 3G
• DOM node count stays reasonable after interactions
• JSHeapUsedSize doesn't spike after table operations
• LayoutCount is proportional to actual layout changes

Location-Dependent Content with Timezone

Tools: emulate_location + emulate_timezone

Content that changes based on location often also has timezone-sensitive elements. Test them together to catch mismatches.

"Set location to Sydney (-33.8688, 151.2093) and timezone to Australia/Sydney. Check the events page — verify event times are shown in AEST, the 'nearby events' section shows Australian locations, and 'happening now' correctly reflects Sydney's current time."

What to check:

• Event times match the emulated timezone
• Location-based filtering uses the emulated coordinates
• "Today", "tomorrow", and relative dates are correct for the timezone
• No server-timezone leakage in displayed times

Print Layout Verification

Tools: emulate_media + inspect_dom

Users still print web pages. Test that your print styles work correctly.

"Set media to print mode. Inspect the invoice page and verify: navigation is hidden (display: none), the layout is single-column, colors are print-friendly (no light gray on white), and the total amount is visible."

What to check:

• Navigation, footer, and interactive elements are hidden
• Background colors are removed or print-appropriate
• Font sizes are appropriate for print
• Page break hints are in place for long content

Building Your Own Combinations

The key insight is that bugs live at intersections. A feature works fine on desktop. It works fine on mobile. It works fine on slow networks. But mobile + slow network + dark mode? That's where the bug is hiding.

When designing test scenarios, think about your actual users:

• What devices do they use? (analytics will tell you)
• Where are they located? (especially important for international products)
• What network conditions do they face?
• Do they use dark mode? (over 80% of mobile users do)
• Do they use assistive technologies?

Combine the conditions your real users face, and you'll catch the bugs they would have found first.