R6.1: Real production import gate

Short answer: Tests must import and invoke real production code. A test that mocks the module it is named after never runs the real code.

Group: Testing and hermeticity. Status: stable. Generated from the rule definitions; do not edit by hand.

Playground: https://brevio.pro/tools/agent-guard-playground?rule=R6.1

What it catches

Real production import gate: tests must import and invoke real production code.

Why

A test that mocks the module it is named after never runs the real code.

A bad example

vi.mock('./a');

A good example

vi.mock('./db');

How it is checked

• The harness’s pre-flight scan of added lines (dev_rules.scan_added_lines); brevio-core scan does not run it.
• A one-line card in the prompt of a slice that touches matching files (dev_rules.slice_micro_rules).

How to silence it

A person can silence one finding with brevio-core: ignore R6.1 -- reason on the line or the line above. Without the reason it does not count. An agent cannot silence it: the agent hook and the MCP tools never honour the comment, and a pull request that adds one is reported until a reviewer allows it. Fixing the code is still the better answer.

A scan reads only the lines you add, so a line that was already in the file is not flagged.

To change what the rule flags, edit its definition in dev_rules.py or code_rules/__init__.py. That is a code change and is reviewed like one.

Related rules

• R6.2 Mutation side-effect assertions
• R6.3 Deterministic condition waits
• R6.4 Hermetic test state isolation
• R6.5 Post-incident regression crystallization
• Every rule