noslop: merge "test_budget.py" and "test_budget_api.py"

[rjpower]

lib/iris/tests/test_budget.py
lib/iris/tests/test_budget_api.py

Someone was having a slop-day. Merge these, remove tests which violate lib/iris/AGENTS.md, no slop.

Claude make a PR.

[claude]

🤖 Plan:

• Read AGENTS.md, iris AGENTS.md, fix-issue/pull-request skills, and both test files
• Post initial plan
• Create branch agent/20260417-fix-4869
• Merge test_budget_api.py into test_budget.py:
  • Parametrized resource_value (4 cases) and compute_effective_band (5 cases)
  • Dropped weak interleave_by_user_two_users_equal_spend (or-branching) and unequal_task_counts (set-membership) duplicates; kept the deterministic three-user round-robin
  • Dropped tautological test_priority_band_values_are_ordered (asserting proto enum int ordering)
  • Dropped banner comments above every function in test_budget_api.py
  • Replaced raw ControllerDB(db_dir=tmp_path) setup with a local state pytest fixture using make_controller_state()
  • Unified helpers: single _launch_request, _start_running_job, _as_admin/_as_user, _set_budget, _get_budget, _launch
  • Switched all service tests to one service fixture with ControllerAuth(provider="static") (needed for the PRODUCTION band check in launch_job)
• Deleted test_budget_api.py
• ./infra/pre-commit.py --fix clean, uv run --with pyrefly pyrefly check clean
• 32 tests pass locally and in CI (see job 71888416300 — every test_budget.py::* line is PASSED at 91-92% progress)
• PR: [iris] Merge test_budget_api.py into test_budget.py; remove slop #4870 (net −337 lines)
• Monitor CI (first run canceled by GH Actions 10m timeout on the full iris-tests job at 93% progress, unrelated to this change; re-triggered via empty commit)