Data Visualization
// Definition
Charts, graphs, maps, and dashboards that render data graphically. Testing concerns span correctness (does the chart reflect the underlying data accurately, including edge cases like empty datasets, single data points, and very large values?), accessibility (colour-blind-safe palettes, ARIA labels on SVG elements, keyboard navigation), and rendering consistency across screen sizes and browsers. Snapshot or pixel-diff testing can catch visual regressions in chart rendering.
// Related terms
Widget
A self-contained, reusable UI component — date picker, rich-text editor, file uploader, chart, or similar — embedded in a page or third-party surface. Testing a widget involves verifying its own behaviour (correct state transitions, keyboard accessibility, error states), its integration with the host form or page (does it emit the right value on change?), and edge cases specific to its type (date picker: leap years, min/max constraints; file uploader: MIME type and size limits). Third-party embedded widgets also require cross-origin and content-security-policy testing.
Accessibility
The practice of designing and testing software so it is usable by people with a wide range of abilities — including users who rely on screen readers, keyboard navigation, voice control, switch access, or high-contrast display modes. In QA, accessibility testing involves both automated scanning and manual verification. Automated tools (axe, Lighthouse, Accessibility Scanner for Android, Accessibility Inspector for iOS) catch structural issues such as missing labels, insufficient colour contrast, and incorrect ARIA roles — typically around a third of all accessibility issues. The remaining two-thirds require testing with actual assistive technologies: VoiceOver on iOS, TalkBack on Android, NVDA or JAWS on Windows. WCAG 2.1 AA is the most widely referenced standard; Level AA compliance is required by law in many jurisdictions (ADA, EN 301 549, AODA). Integrating accessibility checks into CI — for example, running axe as part of a Playwright or Selenium test suite — prevents regressions from being merged undetected.
WCAG
Web Content Accessibility Guidelines — the international standard for accessible web content, organised into four principles (Perceivable, Operable, Understandable, Robust). Levels A, AA, and AAA define increasing conformance. Most regulations target WCAG 2.1 or 2.2 Level AA.