Adds unit tests for previously-uncovered parser helpers in
`server/mdm/microsoft/wstep_csr.go`:
- `parseBase128Int` — single/multi-byte values, non-minimal encoding
(leading `0x80`), truncation, 5-byte cap, `MaxInt32` overflow
- `parseTagAndLength` — short/long-form length, indefinite-length
rejection, non-minimal length and tag, shift overflow
- `parseSANExtension` — DNS, email, URI, IPv4, IPv6, plus malformed IP
length and non-IA5 DNS
- `domainToReverseLabels` — trailing dots, empty middle labels, single
labels
ASN.1 fixtures are built with `cryptobyte.Builder` to match the source
file's existing toolchain — no new dependencies. Pure-Go tests, run in
the `fast` bundle without Docker.
**Related issue:** Refs #33373
# Checklist for submitter
- [x] Added/updated automated tests
<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit
* **Tests**
* Added comprehensive test coverage for certificate Subject Alternative
Name (SAN) parsing: domain label reversal, base‑128 integer decoding
with error classification, ASN.1 tag/length validation and boundary
cases, end‑to‑end parsing of multiple SAN name types (DNS, email,
IPv4/IPv6, URI), and numerous malformed/input edge‑case checks.
<!-- review_stack_entry_start -->
[](https://app.coderabbit.ai/change-stack/fleetdm/fleet/pull/45457)
<!-- review_stack_entry_end -->
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
Rajendra kadam
182307ac3b
