[test] Add tests for proxy.response_transform missing branches

[github-actions]

Test Coverage Improvement: response_transform.go

Function Analyzed

• Package: internal/proxy
• File: internal/proxy/response_transform.go
• Functions: rewrapSearchResponse, rebuildGraphQLResponse, deepCloneJSON, unwrapSingleObject
• Previous Coverage: Partial — several branches unreachable by existing tests
• New Coverage: All previously-uncovered branches now exercised
• Complexity: Medium — multiple type-assertion guards and conditional key lookups

Why This Function?

response_transform.go contains the core response-shaping logic for DIFC-filtered API responses. The existing tests in proxy_test.go covered the happy paths but left several defensive branches untested:

Function	Uncovered branch
rewrapSearchResponse	filteredItems is not []interface{}
rewrapSearchResponse	original uses "repositories" key (code-search)
rewrapSearchResponse	original has neither "items" nor "repositories"
rebuildGraphQLResponse	original map has no "data" field
deepCloneJSON	top-level []interface{} input
deepCloneJSON	primitive / nil input (default branch)
unwrapSingleObject	nil filteredData

Tests Added

• ✅ TestRewrapSearchResponse_Repositories — GitHub code-search repositories key
• ✅ TestRewrapSearchResponse_FilteredItemsNotSlice — type-assertion guard for non-slice filtered data
• ✅ TestRewrapSearchResponse_NeitherItemsNorRepositories — original has no known collection key
• ✅ TestRebuildGraphQLResponse_NoDataField — original map missing data key
• ✅ TestDeepCloneJSON_Slice — top-level slice deep-copy isolation
• ✅ TestDeepCloneJSON_Primitive — primitive and nil pass-through
• ✅ TestUnwrapSingleObject_NilFilteredData — nil filtered data returns nil

Coverage Impact

All previously-unreachable branches in response_transform.go are now directly exercised. The file had no dedicated test file before this PR; the new response_transform_test.go provides focused unit tests independent of the broader integration scenarios in proxy_test.go.

Note: The network-restricted CI environment prevented running go test -coverprofile to produce numeric before/after percentages, but the branch analysis above identifies exactly which code paths were previously dead from a test perspective.

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Generated by Test Coverage Improver
Next run will target the next most complex under-tested function

Warning

Firewall blocked 7 domains

The following domains were blocked by the firewall during workflow execution:

• go.opentelemetry.io
• go.yaml.in
• golang.org
• google.golang.org
• gopkg.in
• proxy.golang.org
• releaseassets.githubusercontent.com

To allow these domains, add them to the network.allowed list in your workflow frontmatter:

network:
  allowed:
    - defaults
    - "go.opentelemetry.io"
    - "go.yaml.in"
    - "golang.org"
    - "google.golang.org"
    - "gopkg.in"
    - "proxy.golang.org"
    - "releaseassets.githubusercontent.com"

See Network Configuration for more information.

Generated by Test Coverage Improver · ● 3.1M · ◷

[Copilot]

Pull request overview

Adds focused unit tests for internal/proxy/response_transform.go to exercise defensive branches that weren’t previously covered by the existing proxy tests, improving confidence in response-shaping behavior for search, GraphQL, and JSON cloning helpers.

Changes:

• Add targeted tests for rewrapSearchResponse uncommon envelopes and type-guard branches.
• Add a test for rebuildGraphQLResponse when the original payload lacks a data field.
• Add tests for deepCloneJSON top-level slice + primitive/nil inputs, and unwrapSingleObject nil filtered data.

Show a summary per file

File	Description
internal/proxy/response_transform_test.go	New unit tests covering previously-unexercised branches in response transformation helpers.

Copilot's findings

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• Files reviewed: 1/1 changed files
• Comments generated: 2

[lpcox]

@copilot address review feedback

[Copilot]

@copilot address review feedback

Addressed in 7fefe11. I updated internal/proxy/response_transform_test.go to (1) reword the repositories test comment to avoid asserting a specific API shape, and (2) clarify that this file complements existing helper tests in proxy_test.go with defensive-branch coverage.