test: add missing coverage for getTaskDuration

[Harshil-Malisetty]

Summary

Requirements for a pull request

• Unit tests related to the change have been updated
• Documentation related to the change has been updated

Adds 10 Cypress component-level tests for the two pure utility functions in src/utils/task.ts:

• getTaskId — resolves a display-friendly task identifier
• getTaskDuration — returns a duration in milliseconds, with live-elapsed-time handling for running tasks

No production code was changed. This is a test-only PR.

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Why this matters

getTaskDuration is called on every task row in the Timeline, DAG, and Task List views. A subtle regression (e.g. returning NaN or a negative number) would silently break duration columns across the UI. These tests lock down the existing behaviour so future changes — like adding killed status support — can be made safely with regression coverage.

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What was added

#	Test case	Input	Expected
1	getTaskId returns task_name when present	{ task_name: 'hello', task_id: 123 }	'hello'
2	getTaskId falls back to task_id	{ task_id: 123 }	'123'
3	Completed task → stored duration	{ status: 'completed', duration: 5000 }	5000
4	Completed task, no duration or timing fields	{ status: 'completed', duration: undefined, finished_at: undefined }	null
5	Failed task, no duration	{ status: 'failed', duration: undefined }	null
6	Running task with started_at → elapsed time	{ status: 'running', started_at: Date.now() - 3000 }	≈ 3000 (±200 ms tolerance)
7	Running task, no started_at	{ status: 'running', started_at: undefined }	null
8	Completed task ignores started_at	{ status: 'completed', duration: 1000, started_at: Date.now() - 9999 }	1000
9	Killed task → stored duration	{ status: 'killed', duration: 4200 }	4200
10	Killed task, no duration	{ status: 'killed', duration: undefined }	null

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Test infrastructure

• Test helper: Uses createTask() from src/utils/testhelper.ts — a factory that spreads partial overrides onto a default Task object, keeping each test focused on the fields under test.
• Runner: Cypress component tests (cypress.config.ts), executed via npx cypress run --component.
• Assertions: Chai-style expect(...).to.equal(...) with greaterThan / lessThan for the elapsed-time tolerance window.

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Files changed

File	Change
src/utils/__tests__/task.test.cypress.ts	New — 10 tests covering getTaskId and getTaskDuration

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How to verify

npx cypress run --component --spec src/utils/__tests__/task.test.cypress.ts

All 10 tests should pass green.

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Design decisions

1. Killed-status tests (cases 9–10): The current getTaskDuration implementation doesn't branch on 'killed' explicitly — killed tasks fall through to the task.duration ? task.duration : null path. The tests document this existing behaviour so that when killed is added as a first-class status (PR feat: distinguish externally killed tasks from code failures (#84) #187), any logic change is caught by CI.

2. Elapsed-time tolerance (±200 ms): Test 6 asserts the running-task elapsed duration is between 2800–3200 ms rather than an exact value, accounting for CI/test-execution jitter.

3. No mocking of Date.now(): The tolerance approach was chosen over mocking to keep the test simple and closer to real runtime behaviour.