test(frontend): add unit tests for FileSaverService

[Ma77Ball]

What changes were proposed in this PR?

• Adds file-saver.service.spec.ts covering FileSaverService; no production code changed.
• Verifies delegation to FileSaver.saveAs for Blob and string payloads.
• Covers the case where filename and options are omitted (undefined is passed through).

Any related issues, documentation, discussions?

Closes: #6448

How was this PR tested?

• Run cd frontend && npx nx test gui --include="**/file-saver.service.spec.ts", expect 4 passed.
• Full frontend suite runs in CI via yarn test:ci, selected by the auto-applied frontend label.

Was this PR authored or co-authored using generative AI tooling?

Co-authored with Claude Opus 4.8 in compliance with ASF

[github-actions]

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Based on the git blame history of the changed files, we recommend the following reviewers:

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[codecov-commenter]

❌ 3 Tests Failed:

Tests completed	Failed	Passed	Skipped
2291	3	2288	3

View the top 3 failed test(s) by shortest run time

src/app/dashboard/service/user/file/file-saver.service.spec.ts > FileSaverService > passes undefined through when filename and options are omitted

Stack Traces | 0.00654s run time

AssertionError: expected "vi.fn()" to be called with arguments: [ Blob{ …(1) }, undefined, undefined ]

Number of calls: 0

 ❯ .../user/file/file-saver.service.spec.ts:62:20
 ❯ src/test-zone-setup.ts:53:33
 ❯ _ZoneDelegate.invoke node_modules/zone.js/fesm2015/zone.js:398:28
 ❯ ProxyZoneSpec.onInvoke node_modules/zone.js/fesm2015/zone-testing.js:2132:39
 ❯ _ZoneDelegate.invoke node_modules/zone.js/fesm2015/zone.js:397:34
 ❯ ProxyZoneSpec.onInvoke node_modules/zone.js/fesm2015/zone-testing.js:2132:39
 ❯ _ZoneDelegate.invoke node_modules/zone.js/fesm2015/zone.js:397:34

src/app/dashboard/service/user/file/file-saver.service.spec.ts > FileSaverService > delegates a Blob payload to saveAs with filename and options

Stack Traces | 0.00693s run time

AssertionError: expected "vi.fn()" to be called 1 times, but got 0 times
 ❯ .../user/file/file-saver.service.spec.ts:47:20
 ❯ src/test-zone-setup.ts:53:33
 ❯ _ZoneDelegate.invoke node_modules/zone.js/fesm2015/zone.js:398:28
 ❯ ProxyZoneSpec.onInvoke node_modules/zone.js/fesm2015/zone-testing.js:2132:39
 ❯ _ZoneDelegate.invoke node_modules/zone.js/fesm2015/zone.js:397:34
 ❯ ProxyZoneSpec.onInvoke node_modules/zone.js/fesm2015/zone-testing.js:2132:39
 ❯ _ZoneDelegate.invoke node_modules/zone.js/fesm2015/zone.js:397:34
 ❯ ProxyZoneSpec.onInvoke node_modules/zone.js/fesm2015/zone-testing.js:2132:39
 ❯ _ZoneDelegate.invoke node_modules/zone.js/fesm2015/zone.js:397:34
 ❯ ProxyZoneSpec.onInvoke node_modules/zone.js/fesm2015/zone-testing.js:2132:39

src/app/dashboard/service/user/file/file-saver.service.spec.ts > FileSaverService > forwards a string payload (e.g. a URL) unchanged

Stack Traces | 0.00825s run time

AssertionError: expected "vi.fn()" to be called with arguments: [ Array(3) ]

Number of calls: 0

 ❯ .../user/file/file-saver.service.spec.ts:54:20
 ❯ src/test-zone-setup.ts:53:33
 ❯ _ZoneDelegate.invoke node_modules/zone.js/fesm2015/zone.js:398:28
 ❯ ProxyZoneSpec.onInvoke node_modules/zone.js/fesm2015/zone-testing.js:2132:39
 ❯ _ZoneDelegate.invoke node_modules/zone.js/fesm2015/zone.js:397:34
 ❯ ProxyZoneSpec.onInvoke node_modules/zone.js/fesm2015/zone-testing.js:2132:39
 ❯ _ZoneDelegate.invoke node_modules/zone.js/fesm2015/zone.js:397:34

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[Copilot]

Pull request overview

This PR adds Vitest unit coverage for the frontend FileSaverService (a thin wrapper around file-saver), improving confidence that the service correctly delegates payloads and optional arguments.

Changes:

• Adds file-saver.service.spec.ts to verify delegation to file-saver’s saveAs for Blob and string inputs.
• Adds assertions for pass-through behavior when filename and options are omitted.

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