internal/tscommon/helpers_test.go -- Test pure string helpers:

1. TestSnakeToLowerCamel -- table-driven:

   • "user_id" -> "userId"
   • "page_number" -> "pageNumber"
   • "simple" -> "simple" (no underscores)
   • "a_b_c" -> "aBC"
   • "" -> "" (empty string)
   • "already_camelCase" -> "alreadyCamelCase" (mixed -- just verify behavior)

2. TestSnakeToUpperCamel -- table-driven:

   • "user_id" -> "UserId"
   • "page_number" -> "PageNumber"
   • "simple" -> "Simple"
   • "" -> ""

3. TestHeaderNameToPropertyName -- table-driven:

   • "X-API-Key" -> "apiKey"
   • "X-Request-ID" -> "requestId"
   • "Content-Type" -> "contentType" (no X- prefix)
   • "X-Tenant-ID" -> "tenantId"

internal/tscommon/types_test.go -- Test type mapping and zero-check functions:

1. TestTSScalarType -- table-driven covering ALL protoreflect.Kind values:

   • StringKind -> "string"
   • BoolKind -> "boolean"
   • Int32Kind, Uint32Kind, FloatKind, DoubleKind -> "number"
   • Int64Kind, Uint64Kind -> "string" (proto3 JSON default)
   • BytesKind -> "string"
   • EnumKind -> "string"
   • MessageKind, GroupKind -> "unknown"

2. TestTSZeroCheck -- table-driven for the string-based function:

   • "string" -> !== ""
   • "bool" -> "" (truthy check)
   • "int32", "uint32", "float", "double" -> !== 0
   • "int64", "uint64" -> !== "0"
   • "enum" -> "" (truthy check, no field context)
   • "unknown_kind" -> !== "" (default fallback)
   • Also test sint32, sfixed32, sint64, sfixed64, fixed32, fixed64

3. TestTSEnumUnspecifiedValue -- Uses protoc to generate real protogen fields. Follow the unwrap_test.go pattern:

   • Run protoc on enum_encoding.proto (which has Status with custom enum_value "unknown" on first value, and Priority without custom values)
   • Parse the generated TS client output to verify: a. Status enum first value uses custom annotation: verify the generated TS contains "unknown" as first value in Status type b. Priority enum first value uses proto name: verify "PRIORITY_LOW" as first value in Priority type
   • This is an integration-style test since we cannot easily construct protogen.Field mocks with extension options. The golden files already cover this, but this test explicitly validates the TSEnumUnspecifiedValue logic via its output in the generated code.

   ALTERNATIVELY (simpler, preferred): Since TSEnumUnspecifiedValue requires a real *protogen.Field with populated Enum and extension options, and mocking protogen is complex, instead write a test that validates the behavior THROUGH the golden file output. Specifically:

   • Read internal/tsclientgen/testdata/golden/enum_encoding_client.ts
   • Verify Status type line contains "unknown" (custom enum_value) as first value
   • Verify Priority type line contains "PRIORITY_LOW" (proto name) as first value
   • This confirms TSEnumUnspecifiedValue + GetEnumValueMapping work correctly

   Name this test TestTSEnumUnspecifiedValue_ViaGoldenOutput with a comment explaining why it validates through golden output rather than direct function calls (protogen.Field requires real protoc extensions).

Important: The package for types_test.go and helpers_test.go is tscommon (same package, internal tests). Import protoreflect for kind constants in types_test.go. Run: cd /Users/sebastienmelki/Documents/documents_sebastiens_mac_mini/Workspace/kompani/sebuf.nosync && go test ./internal/tscommon/ -v -count=1

All tests pass. Expect:

• TestSnakeToLowerCamel (6+ subtests)
• TestSnakeToUpperCamel (4+ subtests)
• TestHeaderNameToPropertyName (4+ subtests)
• TestTSScalarType (10+ subtests)
• TestTSZeroCheck (12+ subtests)
• TestTSEnumUnspecifiedValue_ViaGoldenOutput (2 subtests) All tscommon unit tests pass. Pure functions (TSScalarType, TSZeroCheck, SnakeToLowerCamel, HeaderNameToPropertyName) have table-driven tests covering all branches. TSEnumUnspecifiedValue behavior validated through golden file output for both custom and default enum values.

enum Region {
  REGION_UNSPECIFIED = 0;
  REGION_AMERICAS = 1;
  REGION_EUROPE = 2;
  REGION_ASIA = 3;
}

enum Region {
  REGION_UNSPECIFIED = 0 [(sebuf.http.enum_value) = "unspecified"];
  REGION_AMERICAS = 1 [(sebuf.http.enum_value) = "americas"];
  REGION_EUROPE = 2 [(sebuf.http.enum_value) = "europe"];
  REGION_ASIA = 3 [(sebuf.http.enum_value) = "asia"];
}

cd /Users/sebastienmelki/Documents/documents_sebastiens_mac_mini/Workspace/kompani/sebuf.nosync
go test ./... -count=1