yoi/.yoi/tickets/00001KSYT8D7G/item.md

title	state	created_at	updated_at
Tests: make path fallback tests independent from process env	closed	2026-05-31T10:46:14Z	2026-05-31T10:54:49Z

Background

The environment-variable cleanup removed test-only env surfaces such as INSOMNIA_TEST_* and the Pod runtime command env override. The next issue is that several tests still mutate process-global environment even when they only need to verify deterministic fallback/precedence logic.

The user clarified the intended direction:

• even env vars used by the real application do not need to be read from process env in most tests;
• tests should verify fallback/precedence behavior with direct inputs;
• do not introduce a PathEnv/EnvSnapshot abstraction or a shared test-support crate just to preserve process-env mutation;
• write the fallback helpers directly and narrowly where needed.

This ticket starts with path resolution, where the behavior is centralized and the env mutation is avoidable.

Requirements

• In manifest::paths, separate fallback/precedence logic from process env reads enough that fallback tests can call pure helpers with direct Option<PathBuf>-style inputs.
• Prefer small per-key helpers over a general PathEnv struct/trait.
  • Example shape: resolve_config_dir_from_parts(...), resolve_data_dir_from_parts(...), resolve_runtime_dir_from_parts(...), or equivalent private helpers.
  • Keep helper visibility private or pub(crate) only if needed by nearby tests.
• Keep runtime behavior unchanged:
  • public path functions still read the same supported env vars in the same order;
  • empty env values keep the current unset-equivalent behavior;
  • resource lookup fallback behavior remains compatible with packaging/dev use.
• Convert path fallback tests that currently use std::env::set_var / remove_var to direct helper tests where possible.
• Do not add a new helper crate or broad env abstraction.
• Do not remove credential env behavior in this ticket; that belongs to manifest-profile-encrypted-secrets.
• Do not attempt to eliminate subprocess integration env setup if a spawned process still needs runtime isolation; report any remaining env mutation rather than forcing risky API changes.

Non-goals

• Removing all env reads from production code.
• Removing provider credential env support.
• Redesigning runtime directory authority or Pod process startup.
• Introducing test-support / EnvSnapshot / trait-based environment abstraction.
• Changing documented path semantics.

Acceptance criteria

• manifest::paths fallback/precedence tests no longer mutate process-global environment just to test fallback order.
• The fallback order documented in docs/environment.md still matches the code.
• Any remaining set_var / remove_var in touched tests is either eliminated or explicitly justified in the implementation report.
• No new environment variable surface is introduced.
• cargo fmt --check, cargo test -p manifest paths, relevant affected tests, cargo check -p manifest, ./tickets.sh doctor, and git diff --check pass.