tdd.md

description	Enforce strict TDD workflow - write test first, see it fail, then implement
allowed-tools	AskUserQuestion, Bash, Read, Glob, Grep, Edit, Write, Task
argument-hint	<feature-description> [--shell\|--python] [--file <test_file>]

TDD TDD TDD - Strict Test-Driven Development

Enforce the classic Red -> Green -> Refactor cycle. Tests are written FIRST, implementation comes SECOND.

"TDD TDD TDD" - the repetition is intentional. This skill enforces discipline.

ODS has two test ecosystems: Shell (BATS + bash assert) and Python (pytest). This skill handles both.

Arguments

$ARGUMENTS - Feature description and options:
- First part: Feature description in quotes or as text
- --shell - Write shell/BATS test (default for installers/, scripts/, ods-cli)
- --python - Write Python/pytest test (default for dashboard-api/)
- --file <path> - Explicit test file path

The Three Laws of TDD

You may not write production code until you have written a failing test
You may not write more test than is sufficient to fail
You may not write more production code than is sufficient to pass the test

Philosophy: Ask Early, Ask Often

This skill should liberally use AskUserQuestion at decision points. TDD involves judgment about what to test, test granularity, and when the implementation is "done." The user should direct these choices.

Before writing the test — confirm what behavior to test and test type
After RED phase — validate that the failure is the right kind before implementing
After GREEN phase — ask if the implementation approach is acceptable
After each cycle — ask whether to iterate or stop

Workflow

Phase 0: Understand the Feature

Before writing anything:

Parse $ARGUMENTS to extract feature description and flags
Analyze the feature - what behavior needs to be tested?
Determine test ecosystem (Shell or Python) based on the feature area:

Shell Test Locations (BATS)

Feature Area	Test Path	Implementation Path
Installer libraries	`tests/bats-tests/<lib>.bats`	`installers/lib/<lib>.sh`
Installer phases	`tests/bats-tests/<phase>.bats`	`installers/phases/<phase>.sh`
Scripts	`tests/test-<script>.sh`	`scripts/<script>.sh`
CLI features	`tests/test-<feature>.sh`	`ods-cli`
Compose selection	`tests/bats-tests/compose-select.bats`	`installers/lib/compose-select.sh`

Python Test Locations (pytest)

Feature Area	Test Path	Implementation Path
API routers	`extensions/services/dashboard-api/tests/test_<router>.py`	`extensions/services/dashboard-api/routers/<router>.py`
API helpers	`extensions/services/dashboard-api/tests/test_helpers.py`	`extensions/services/dashboard-api/helpers.py`
Security	`extensions/services/dashboard-api/tests/test_security.py`	`extensions/services/dashboard-api/security.py`
GPU detection	`extensions/services/dashboard-api/tests/test_gpu.py`	`extensions/services/dashboard-api/gpu.py`

Confirm test approach with user:

AskUserQuestion:
  question: "Here's my understanding. Does this test plan look right?"
  header: "Test plan"
  multiSelect: false
  options:
    - label: "Looks good — write the test"
      description: "Test: <what behavior to test>. Type: <shell/python>. File: <test path>"
    - label: "Different behavior to test"
      description: "I want to test something different than what you described"
    - label: "Different test type"
      description: "Use <shell instead of python / vice versa>"
    - label: "Multiple test cases"
      description: "I want to test several scenarios — let me list them"

Check existing tests for patterns and fixtures.

For Shell/BATS:
```
ls ods/tests/bats-tests/
```
For Python:
```
ls ods/extensions/services/dashboard-api/tests/
```

Phase 1: RED - Write Failing Test

CRITICAL: Write the test FIRST. No implementation code yet.

Shell (BATS) Test Template

#!/usr/bin/env bats
# Tests for <module>

load '../bats/bats-support/load'
load '../bats/bats-assert/load'

setup() {
    # Stub logging functions that lib modules expect
    error() { echo "ERROR: $*" >&2; return 1; }
    export -f error
    log() { :; }
    export -f log

    # Source the library under test
    source "$BATS_TEST_DIRNAME/../../installers/lib/<module>.sh"
}

@test "<function_name>: <expected behavior>" {
    # Arrange
    SOME_VAR="test-value"

    # Act
    <function_name>

    # Assert
    assert_equal "$RESULT_VAR" "expected-value"
}

Python (pytest) Test Template

"""Tests for <module>."""

import<
8000
/span> pytest
from unittest.mock import AsyncMock, MagicMock, patch


class TestFeatureName:
    """Tests for [feature description]."""

    def test_feature_does_expected_thing(self, test_client):
        """[Feature] should [expected behavior]."""
        # Arrange
        # ... setup test data

        # Act
        response = test_client.get("/endpoint", headers=test_client.auth_headers)

        # Assert
        assert response.status_code == 200
        assert response.json()["key"] == "expected"

Step 1.2: Run Test and VERIFY IT FAILS

For Shell/BATS:

cd ods && bats tests/bats-tests/<module>.bats

For Python:

cd ods/extensions/services/dashboard-api && pytest tests/test_<module>.py -v -k "test_function_name"

STOP AND CHECK:

Does the test fail?
Does it fail for the RIGHT reason? (e.g., ImportError, missing function, assertion error)

If test PASSES without implementation:

The test is invalid. It doesn't test new behavior. REWRITE IT.

If test fails with wrong error:

The test has setup issues. Fix the test setup, then continue.

If test fails with assertion error or import error:

Perfect! This is the RED state. Proceed to GREEN phase.

Step 1.3: Document the Expected Failure

Before moving on, note:

What error message appeared
What the test is actually testing
What implementation is needed

Phase 2: GREEN - Minimal Implementation

RULE: Write the MINIMUM code to make the test pass. Nothing more.

Step 2.1: Implement Just Enough

# BAD - Over-engineering in shell
resolve_something() {
    local input="$1"
    log "Processing $input"
    validate_input "$input" || { error "Invalid"; return 1; }
    local cached; cached=$(check_cache "$input")
    if [ -n "$cached" ]; then echo "$cached"; return 0; fi
    # ... complex logic
}

# GOOD - Minimal implementation for test
resolve_something() {
    local input="$1"
    echo "resolved-$input"
}

Step 2.2: Run Test and VERIFY IT PASSES

For Shell/BATS:

cd ods && bats tests/bats-tests/<module>.bats

For Python:

cd ods/extensions/services/dashboard-api && pytest tests/test_<module>.py -v -k "test_function_name"

STOP AND CHECK:

Does the test pass?
Did you write ONLY what was needed?

If test still fails:

Debug the implementation. Do NOT modify the test (unless it has a bug).

If test passes:

GREEN state achieved. Proceed to REFACTOR phase.

Phase 3: REFACTOR - Clean Up

RULE: Improve code quality while keeping tests GREEN.

Step 3.1: Check for Code Smells

Review both test and implementation for:

Duplicate code
Poor naming
Long functions (> 30 lines)
Deep nesting (> 3 levels)

Step 3.2: Refactor If Needed

Make small improvements:

Extract helper functions
Improve variable names
Remove duplication

Step 3.3: Run Tests After Each Change

For Shell/BATS:

cd ods && bats tests/bats-tests/<module>.bats

For Python:

cd ods/extensions/services/dashboard-api && pytest tests/test_<module>.py -v

If test fails after refactoring:

UNDO the refactoring. Refactoring should never break tests.

Step 3.4: Run Linting

For Shell:

cd ods && bash -n <modified-file> && make lint

For Python:

cd ods && python3 -m py_compile extensions/services/dashboard-api/<modified-file>

Step 3.5: Run Full Test Suite

# Shell: ensure no regressions
cd ods && make test && make bats

# Python: ensure no regressions
cd ods/extensions/services/dashboard-api && pytest tests/ -v

Iteration

After completing one Red-Green-Refactor cycle, ask the user:

AskUserQuestion:
  question: "Cycle complete — test passes and code is clean. Continue with more test cases?"
  header: "Iterate"
  multiSelect: false
  options:
    - label: "Next test case"
      description: "Suggested next: <edge case or error condition based on feature>"
    - label: "I'll specify the next test"
      description: "I have a specific scenario I want tested next"
    - label: "Done — feature complete"
      description: "Current test coverage is sufficient for this feature"
    - label: "Run full test suite"
      description: "Verify no regressions before stopping"

Common progression:

Happy path test
Edge case tests
Error handling tests
Integration tests (if needed)

Anti-Patterns to AVOID

DON'T: Write Implementation First

# WRONG - This is not TDD
1. Write function
2. Write test
3. Test passes

# RIGHT - TDD way
1. Write test
2. Test fails (RED)
3. Write function
4. Test passes (GREEN)
5. Refactor

DON'T: Write Tests That Can't Fail

# BAD - This BATS test is useless
@test "true returns true" {
    run true
    assert_success
}

# GOOD - Testing behavior
@test "resolve_tier_config: tier 0 returns error" {
    TIER=0
    run resolve_tier_config
    assert_failure
}

DON'T: Over-Engineer in GREEN Phase

# BAD - Too much for first iteration
resolve_tier_config() {
    validate_tier "$TIER" || { error "Invalid tier"; return 1; }
    log "Resolving tier $TIER"
    case "$TIER" in
        1) TIER_NAME="Entry Level"; LLM_MODEL="qwen3.5-9b" ;;
        # ... 10 more tiers with caching, logging, etc.
    esac
}

# GOOD - Start simple, add complexity via new tests
resolve_tier_config() {
    case "$TIER" in
        1) TIER_NAME="Entry Level"; LLM_MODEL="qwen3.5-9b" ;;
    esac
}

Example Session

User: /tdd "add validation for GPU tier 0 in tier-map.sh"

Phase 0 - Understand:

Feature: Validate that tier 0 is rejected
Test type: Shell (BATS)
Test location: tests/bats-tests/tier-map.bats
Implementation: installers/lib/tier-map.sh

Phase 1 - RED:

# tests/bats-tests/tier-map.bats (append)
@test "resolve_tier_config: tier 0 returns error" {
    TIER=0
    run resolve_tier_config
    assert_failure
    assert_output --partial "ERROR"
}

Run: cd ods && bats tests/bats-tests/tier-map.bats --filter "tier 0" Result: FAILS (tier 0 falls through with no error) - Good!

Phase 2 - GREEN:

# installers/lib/tier-map.sh — add to resolve_tier_config()
resolve_tier_config() {
    if [ "${TIER:-0}" -eq 0 ]; then
        error "GPU tier 0 is unsupported — no compatible GPU detected"
        return 1
    fi
    # ... existing cases
}

Run: cd ods && bats tests/bats-tests/tier-map.bats --filter "tier 0" Result: PASSES - Good!

Phase 3 - REFACTOR:

Check naming: "unsupported" is clear
Run linting: bash -n installers/lib/tier-map.sh
Run full suite: make test && make bats

Iterate: Next test - negative tier value, non-numeric tier...

ODS-Specific Patterns

BATS Test Setup

All BATS tests in ODS follow this pattern:

load '../bats/bats-support/load'
load '../bats/bats-assert/load'

setup() {
    # Stub logging functions the lib expects
    error() { echo "ERROR: $*" >&2; return 1; }
    export -f error
    log() { :; }
    export -f log

    # Source the library under test
    source "$BATS_TEST_DIRNAME/../../installers/lib/<module>.sh"
}

Python Test Fixtures (from conftest.py)

Available fixtures for dashboard-api tests:

test_client - FastAPI TestClient with Bearer auth (use test_client.auth_headers)
install_dir - Isolated install directory with .env file
data_dir - Isolated data directory for bootstrap/token files
setup_config_dir - Isolated config directory for setup/persona files
mock_aiohttp_session - Factory for mock aiohttp sessions

Mocking External Services (Python)

from unittest.mock import AsyncMock, patch

def test_with_mocked_service(test_client, mock_aiohttp_session):
    """Test with mocked external HTTP call."""
    session = mock_aiohttp_session(status=200, json_data={"ok": True})
    with patch("helpers._get_aio_session", AsyncMock(return_value=session)):
        response = test_client.get("/health", headers=test_client.auth_headers)
        assert response.status_code == 200

Quick Reference

Phase	Action	Verify
RED	Write test	Test FAILS
GREEN	Write minimal impl	Test PASSES
REFACTOR	Clean up	Tests still PASS

# Shell quick commands
cd ods && bats tests/bats-tests/<lib>.bats          # Run BATS test
cd ods && make test && make bats                      # Run all shell tests
cd ods && bash -n <file> && make lint                 # Lint shell

# Python quick commands
cd ods/extensions/services/dashboard-api && pytest tests/test_<module>.py -v -k "test_name"
cd ods/extensions/services/dashboard-api && pytest tests/ -v   # Run all
cd ods && make lint                                             # Lint all

Notes

Always check existing BATS tests in tests/bats-tests/ for patterns before writing new ones
Always check dashboard-api/tests/conftest.py for available pytest fixtures
Shell tests use set -euo pipefail implicitly via BATS
BATS tests use assert_equal, assert_success, assert_failure, assert_output from bats-assert
Python tests: do NOT add try/except in tests (Let It Crash principle)
Coverage is tracked structurally for shell (which modules have BATS tests vs not)

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tdd.md

tdd.md

TDD TDD TDD - Strict Test-Driven Development

Arguments

The Three Laws of TDD

Philosophy: Ask Early, Ask Often

Workflow

Phase 0: Understand the Feature

Shell Test Locations (BATS)

Python Test Locations (pytest)

Phase 1: RED - Write Failing Test

Shell (BATS) Test Template

Python (pytest) Test Template

Step 1.2: Run Test and VERIFY IT FAILS

Step 1.3: Document the Expected Failure

Phase 2: GREEN - Minimal Implementation

Step 2.1: Implement Just Enough

Step 2.2: Run Test and VERIFY IT PASSES

Phase 3: REFACTOR - Clean Up

Step 3.1: Check for Code Smells

Step 3.2: Refactor If Needed

Step 3.3: Run Tests After Each Change

Step 3.4: Run Linting

Step 3.5: Run Full Test Suite

Iteration

Anti-Patterns to AVOID

DON'T: Write Implementation First

DON'T: Write Tests That Can't Fail

DON'T: Over-Engineer in GREEN Phase

Example Session

ODS-Specific Patterns

BATS Test Setup

Python Test Fixtures (from conftest.py)

Mocking External Services (Python)

Quick Reference

Notes

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TDD TDD TDD - Strict Test-Driven Development

Arguments

The Three Laws of TDD

Philosophy: Ask Early, Ask Often

Workflow

Phase 0: Understand the Feature

Shell Test Locations (BATS)

Python Test Locations (pytest)

Phase 1: RED - Write Failing Test

Shell (BATS) Test Template

Python (pytest) Test Template

Step 1.2: Run Test and VERIFY IT FAILS

Step 1.3: Document the Expected Failure

Phase 2: GREEN - Minimal Implementation

Step 2.1: Implement Just Enough

Step 2.2: Run Test and VERIFY IT PASSES

Phase 3: REFACTOR - Clean Up

Step 3.1: Check for Code Smells

Step 3.2: Refactor If Needed

Step 3.3: Run Tests After Each Change

Step 3.4: Run Linting

Step 3.5: Run Full Test Suite

Iteration

Anti-Patterns to AVOID

DON'T: Write Implementation First

DON'T: Write Tests That Can't Fail

DON'T: Over-Engineer in GREEN Phase

Example Session

ODS-Specific Patterns

BATS Test Setup

Python Test Fixtures (from conftest.py)

Mocking External Services (Python)

Quick Reference

Notes