Add CSV encoding tests for enum and extensible enum arrays

[Copilot]

Adds spector scenario tests for enum arrays and union-as-enum arrays with CSV delimiters, following the existing string array test pattern.

Changes

• Enum definitions: Added Colors fixed enum and ColorsExtensibleEnum union for test data
• Models: 8 new model definitions with @encode(ArrayEncoding.*) decorators
  • 4 for fixed enum arrays (comma, space, pipe, newline delimited)
  • 4 for extensible enum arrays (comma, space, pipe, newline delimited)
• Operations: 8 new @scenario operations testing request/response roundtrip for each delimiter type
• Mock APIs: 8 scenario mock implementations reusing existing helper pattern

Example

enum Colors {
  Blue: "blue",
  Red: "red",
  Green: "green",
}

model CommaDelimitedEnumArrayProperty {
  @encode(ArrayEncoding.commaDelimited)
  value: Colors[];
}

@scenario
@post
op enumCommaDelimited(@body body: CommaDelimitedEnumArrayProperty): CommaDelimitedEnumArrayProperty;
// Expected: {"value": "blue,red,green"}

All tests validate that enum arrays serialize as delimited strings (e.g., "blue,red,green") rather than JSON arrays.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>CSV encoding for model properties Scenario tests</issue_title>
<issue_description>Add http-specs tests for array encoding, including all four encode. Add a new folder under packages/http-specs/specs/encode.</issue_description>

<agent_instructions>Add another spector test of enum array and union as enum array, according to previous test for string array.</agent_instructions>

Comments on the Issue (you are @copilot in this section)

@lirenhe Re-open this item to add the support of Enum as string

• Fixes CSV encoding for model properties Scenario tests #9029

---

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commit: 4116642

[github-actions]

All changed packages have been documented.

• ✅ @typespec/http-specs

Show changes

@typespec/http-specs - feature ✏️

Add array encoding test for enum and extensible enum arrays.

[XiaofeiCao]

nit, should we consider edge cases, e.g. empty array("")?

[weidongxu-microsoft]

I've had a simple one. #9330

But fine to use this more complete case.

[tadelesh]

I've had a simple one. #9330

But fine to use this more complete case.

Sorry for not noticing your PR. Let me close your one.

[tadelesh]

@timotheeguerin Could you help to reivew?