add-edge-test

name	add-edge-test
description	"

Before You Start

• tests/edge/corrupt_state.bats — bug-documenting test pattern (documents known silent failure)
• tests/edge/special_characters.bats — how to test shell expansion edge cases
• tests/edge/numeric_edge_cases.bats — bc arithmetic boundary tests
• tests/helpers/test_helper.bash — _common_setup (all 9 libs sourced, including synthesize.sh's nullglob side effect)

When to Use Edge Tests vs Unit Tests

Scenario	Location
Testing a known bug (regression)	tests/edge/
Testing CLI argument parsing	tests/edge/cli_args.bats
Testing budget boundary conditions	tests/edge/budget_exhaustion.bats
Testing a lib function's normal behavior	tests/unit/
Testing a shell expansion quirk	tests/edge/

Steps

1. Create the test file

touch tests/edge/<domain>.bats

File header:

#!/usr/bin/env bats
# Edge cases for <domain>: <one-line description of what failure domain this covers>

setup() {
    load '../helpers/test_helper'
    _common_setup
    # Only add mock_claude if testing agent execution paths:
    # load '../helpers/mock_claude'
    # setup_mock_claude
}

teardown() {
    _common_teardown
}

2. Write bug-documenting tests

Edge tests document actual behavior (including bugs), not ideal behavior. The pattern from tests/edge/corrupt_state.bats:

@test "cost files without pipe delimiters are silently treated as zero spend" {
    # Inject malformed cost file (no pipe separators)
    echo "50.00" > "$WORK_DIR/costs/agent.cost"

    run check_budget
    # Documents the bug: malformed files contribute $0, not $50
    assert_success  # budget check passes even though it should detect $50
}

If you are documenting a known bug, add a comment explaining the bug and why it isn't fixed yet.

3. Manual state injection

Edge tests often need specific preconditions. Inject state directly:

@test "bc produces .20 not 0.20 for values under 1" {
    # Set budget so AGENT_BUDGET will be fractional
    TOTAL_BUDGET="1.00"
    _common_setup  # re-source with new budget

    # bc with scale=2: result is '.20' not '0.20'
    local result
    result=$(echo 'scale=2; 1/5' | bc)
    [[ "$result" == ".20" || "$result" == "0.20" ]]
}

4. nullglob side effect tests

Because synthesize.sh sets shopt -s nullglob globally at source time (via _common_setup), edge tests can test nullglob interactions:

@test "empty costs directory does not block budget check" {
    # With nullglob: *.cost matches nothing, expands to empty string
    rm -f "$WORK_DIR/costs"/*.cost
    run check_budget
    assert_success
}

Note: You cannot test non-nullglob behavior in isolation — _common_setup always sources synthesize.sh, which always sets nullglob.

5. Special character edge cases

For shell expansion bugs (see tests/edge/special_characters.bats):

@test "prompts with apostrophes use @file form to avoid expansion" {
    local prompt_file="$TEST_TMPDIR/prompt.txt"
    echo "This project's goal is testing" > "$prompt_file"

    make_claude_envelope '{}' '0.10' > "$MOCK_CLAUDE_RESPONSE"

    run run_agent "test-agent" "@${prompt_file}" \
        "${SCRIPT_DIR}/schemas/identity.json" "Read" "haiku"
    assert_success
}

Verify

make test-edge

Or for a single file:

docker run --rm -v "$(pwd)":/workspace -w /workspace \
    ghcr.io/joelbarmettleruzh/ultrainit-test:latest \
    bats tests/edge/<domain>.bats

Common Mistakes

1. Testing current (buggy) behavior as if it were correct — the project rule says "write tests to test the actually correct behaviour". For bug-documenting tests, clearly label them as documenting a known bug with a comment, not as asserting the correct behavior.

2. Forgetting nullglob is always active — synthesize.sh sets shopt -s nullglob at source time. All glob patterns in all tests expand differently than they would in isolation. Tests that rely on a glob pattern returning the literal string when no files match will silently pass for the wrong reason.