Description

This PR adds unit tests for ten packages that were previously untested, addressing the unit testing coverage issues tracked in the repository. The new test files are self-contained black-box test packages (_test suffix) following the conventions already used elsewhere in the codebase.

The new test files and the issues they target:

No production code was modified. Coverage is achieved through small, focused unit tests on the existing exported surface of each package:

• textutil: GetTemplateLikeString (LIKE → template semantics) and ExpandPlaceholders (placeholder expansion), both existing tests preserved and extended with additional cases.
• txncounter: NewTxnCounterManager constructor, GetCurrentGenerationID, GetCurrentSessionID, GetNextInsertID, GetNextTxnID including concurrent access.
• sqltypeutil: InterfaceToSQLType covering string, bool, int64, float64, nil, []byte, and error paths.
• kstore: GetKStore singleton access, Put, Del, Min operations including concurrent access.
• nativedb: NewColumn / Column interface (GetName, GetType, GetWidth, SetWidth) and NewSelect / Select interface (GetColumns, GetRows).
• providerconfig: ReadProviderConfig covering valid YAML, nested YAML, empty YAML, file-not-found, invalid YAML, list values, and special characters.
• metadatavisitors: NewTemplatedProduct / TemplatedProduct interface (GetBody, GetPlaceholder).
• iqlerror: GetStatementNotSupportedError message formatting and HandlePanic recovery behavior.
• sqlstream: NewStaticMapStream / StaticMapStream (streaming.MapStream implementation) with Write and Read operations.
• internaldto: NewBasicPrimitiveContext / BasicPrimitiveContext interface (GetWriter, GetErrWriter, GetAuthContext).

Type of change

• Bug fix (non-breaking change to fix a bug).
• Feature (non-breaking change to add functionality).
• Breaking change.
• Other (eg: documentation change). Please explain: adds unit tests only, no production code changes.

Issues referenced

• Unit testing for package primitive_context #235 — Unit testing for package internaldto (internal_data_transfer/internaldto)
• Unit testing for package iqlerror #237 — Unit testing for package iqlerror

Evidence

Local unit test run, scoped to the ten new/updated packages, with the same build tag CI uses (sqlite_stackql):

$ go test -v --tags sqlite_stackql ./pkg/textutil/...
ok  	github.com/stackql/stackql/pkg/textutil	0.008s

$ go test -v --tags sqlite_stackql ./pkg/txncounter/...
ok  	github.com/stackql/stackql/pkg/txncounter	0.007s

$ go test -v --tags sqlite_stackql ./pkg/sqltypeutil/...
ok  	github.com/stackql/stackql/pkg/sqltypeutil	0.012s

$ go test -v --tags sqlite_stackql ./internal/stackql/kstore/...
ok  	github.com/stackql/stackql/internal/stackql/kstore	0.009s

$ go test -v --tags sqlite_stackql ./internal/stackql/nativedb/...
ok  	github.com/stackql/stackql/internal/stackql/nativedb	0.007s

$ go test -v --tags sqlite_stackql ./internal/stackql/providerconfig/...
ok  	github.com/stackql/stackql/internal/stackql/providerconfig	0.011s

$ go test -v --tags sqlite_stackql ./internal/stackql/metadatavisitors/...
ok  	github.com/stackql/stackql/internal/stackql/metadatavisitors	0.029s

$ go test -v --tags sqlite_stackql ./internal/stackql/iqlerror/...
ok  	github.com/stackql/stackql/internal/stackql/iqlerror	0.004s

$ go test -v --tags sqlite_stackql ./internal/stackql/sqlstream/...
ok  	github.com/stackql/stackql/internal/stackql/sqlstream	0.013s

$ go test -v --tags sqlite_stackql ./internal/stackql/internal_data_transfer/internaldto/...
ok  	github.com/stackql/stackql/internal/stackql/internal_data_transfer/internaldto	0.022s

Full local suite (go test --tags sqlite_stackql ./...) is green — no regressions introduced.

Checklist:

• A full round of testing has been completed, and there are no test failures as a result of these changes.
• The changes are covered with functional and/or integration robot testing. (see Variations)
• The changes work on all supported platforms. (no platform-specific code; pure unit tests using the standard library + existing test dependencies)
• Unit tests pass locally, as per the developer guide.
• Robot tests pass locally, as per the developer guide. (see Variations)
• Linter passes locally, as per the developer guide. (gofmt clean; follows the package <name>_test black-box convention already used elsewhere in the codebase)

Variations

• Robot tests: this PR only adds unit tests for self-contained internal helpers. None of the touched packages drive provider / SQL / HTTP / wire behavior that the robot scenarios exercise, so no robot coverage is required for these specific changes. Robot suite should be unaffected (no production code changed).
• Linter: golangci-lint v2.5.0 is not installed in the development environment used to author these tests, so the lint pass was validated by gofmt-clean formatting and adherence to existing test patterns. CI's lint job will be the authoritative check.

Tech Debt

Zero technical debt results from this change set. The new test files are self-contained, follow the established _test black-box package convention, and add no new dependencies.