Timezone-Sensitive Date Testing
Relevant source files
The following files were used as context for generating this wiki page:
Timezone-sensitive date testing in StatusBeam ensures that uptime data, incident timelines, and RSS/Atom feeds are accurately represented across different geographic locales. Since StatusBeam is a CDN-native status page generator running on Cloudflare's edge platform, it must handle global time synchronization and localization without relying on a centralized origin server.
The testing strategy focuses on validating internationalization (i18n) for CJK (Chinese, Japanese, Korean) and English locales, ensuring that relative time strings (e.g., "3h ago") and absolute timestamps in feeds comply with standardized formats like ISO-8601 and RFC-822 while remaining localized for the end user.
Sources: ARCHITECTURE.md:12-18, README.md:175-180, packages/core/src/incidents.test.ts:71-85
Core Testing Mechanisms
The project utilizes bun:test to execute unit tests that validate date logic. A primary focus is the packages/core module, which contains framework-free domain logic for status derivation and i18n.
Relative Time Localization
The relativeTime function is a critical component tested for its ability to localize time differences using Intl.RelativeTimeFormat. Tests ensure that sub-minute buckets are handled correctly (e.g., "just now" in English vs. localized equivalents in Japanese or Korean).
The diagram above illustrates the logic flow for generating localized relative time strings as validated in the test suite.
Sources: packages/core/src/incidents.test.ts:71-92, ARCHITECTURE.md:46-50
Feed Timestamp Validation
StatusBeam generates RSS and Atom feeds for incident history. Testing ensures these feeds use the correct date serialization:
- Atom Feeds: Must use ISO-8601 strings (e.g.,
2026-01-01T00:00:00.000Z). - RSS Feeds: Must use RFC-822 / UTC strings (e.g.,
Thu, 01 Jan 2026 01:00:00 GMT).
Sources: packages/core/src/feed.test.ts:98-105, packages/core/src/feed.test.ts:114-121
Robustness and Fallback Logic
Testing also covers "poisoned" or malformed data to ensure the status page remains resilient. If a timestamp is unparseable, the system is designed to degrade gracefully rather than crashing the render.
| Test Scenario | Expected Behavior | Source |
|---|---|---|
| Unparseable Timestamp | Fall back to raw string or Unix Epoch (1970-01-01) | packages/core/src/feed.test.ts:153-164 |
| Missing Date Fields | Fall back to startedAt or current time | packages/core/src/feed.test.ts:46-51 |
Non-finite now value | Prevent RangeError or "Invalid Date" output | packages/core/src/feed.test.ts:166-173 |
| Sub-minute intervals | English: "just now"; Others: Localized seconds | packages/core/src/incidents.test.ts:74-76 |
Incident Timeline Synchronization
Incidents are tracked through a lifecycle (Investigating → Identified → Monitoring → Resolved). Testing validates that these updates are sorted correctly regardless of the order they are received from the data store (D1/KV).
The sequence shows how the system processes raw database timestamps into structured timelines for both the web UI and external feeds.
Sources: packages/core/src/incidents.test.ts:20-30, packages/core/src/feed.test.ts:38-44, README.md:124-129
Technical Implementation Details
The testing suite relies on injected "now" providers to ensure deterministic tests. For example, when testing checkSite, a now function is passed to simulate the passage of time for response-time calculations.
// Example from check.test.ts illustrating timezone-independent duration testing
it('maps a successful fetch to a check result', async () => {
let t = 0
const result = await checkSite(site, {
fetchImpl: () => Promise.resolve(new Response('', { status: 200 })),
now: () => (t += 50), // Injected clock
})
expect(result.status).toBe('up')
})
Sources: packages/core/src/check.test.ts:50-58
Summary
Timezone-sensitive date testing in StatusBeam ensures the reliability of the edge-rendered status page. By strictly validating localized string formatting, fallback mechanisms for malformed timestamps, and standardized feed serialization, the project maintains high availability and accuracy for a global audience. The use of pure, framework-free functions in packages/core allows these date logic tests to run independently of Cloudflare or Astro runtimes.
Sources: ARCHITECTURE.md:88-92, README.md:182-185