TEST-006: Vitest unit tests for all 9 React components (~100% coverage)

[Copilot]

No test infrastructure existed for the frontend. This adds a full Vitest + Testing Library setup covering all 9 components in src/components/.

Test infrastructure

• Dependencies: vitest, @vitest/coverage-v8, @testing-library/react, @testing-library/jest-dom, @testing-library/user-event, jsdom
• Config: Vitest wired into vite.config.ts (jsdom env, v8 coverage scoped to src/components/)
• Scripts: npm test · npm run test:watch · npm run test:coverage
• Setup: src/test/setup.ts imports @testing-library/jest-dom matchers

Test files (147 tests total, all passing)

File	Tests	Key scenarios
PlayerCard.test.tsx	21	position badge colors, optional fields, click handler
TeamCard.test.tsx	18	conference badge colors, logo, showStats, click handler
GameCard.test.tsx	26	status badge colors, scores, winner highlight, logos + onError, click handler
PlayerList.test.tsx	14	loading/error/empty states, search + position filters
TeamList.test.tsx	14	loading/error/empty states, conference filter, grouping headers
GameList.test.tsx	16	loading/error/empty states, status/team filters, date grouping, sort order
StatCard.test.tsx	23	value formatting (decimal/percent/integer/default), trend arrows, PlayerStatsGrid optional stats
Layout.test.tsx	5	children rendering, footer, semantic roles
Navigation.test.tsx	10	nav links, active state highlighting per route, hrefs

Coverage

All files  | 100% Stmts | 99.44% Branch | 100% Funcs | 100% Lines

The single uncovered branch (TeamList.tsx:76 — team.conference \|\| 'Unknown') is dead code: teams are pre-filtered to 'East'/'West' before reaching the groupBy reducer, making the fallback unreachable in practice.

Original prompt

TEST-006: Write unit tests for React components

Work Item Details

Note: Please focus on the descriptions and information that provide context about the task requirements, functionality, and implementation details. Dates, priorities, and administrative metadata are less relevant for coding tasks.

Description

Unit Tests for React Components

Test 9 components in frontend/src/components/ using Vitest + Testing Library.

Components

• PlayerCard.tsx (85 lines): renders player name, position badge (color-coded PG/SG/SF/PF/C), jersey number, height/weight/college; click handler fires
• TeamCard.tsx: renders team name, logo, conference, division
• GameCard.tsx: renders home/away teams, scores, date, status
• PlayerList.tsx: renders list of PlayerCards, loading state, empty state
• TeamList.tsx: renders list of TeamCards
• GameList.tsx: renders list of GameCards with date grouping
• StatCard.tsx: renders stat label + value
• Layout.tsx: renders header, navigation, children content
• Navigation.tsx: renders nav links, active state highlighting

Work item: AB#1734
Created via Azure DevOps

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