E2E tests for array builtins (CIP-0138, Batch 6, PV 11)

[Unisay]

Context

• What: Add end-to-end tests for PlutusV3 array builtin functions (CIP-0138)
• Why: Validate on-chain behavior of indexArray, lengthOfArray, and listToArray builtins introduced in Plutus Core Batch 6
• Issue: Related to plutus-private#1921, plutus-private#1922
• Dependency: BLOCKED until Protocol Version 11 support is added to cardano-node-tests (expected early next week per Martin)

Approach

Implemented E2E tests following the established pattern from Batch 5 builtins (bitwise, RIPEMD-160). Key design decisions:

Test Organization:

• Created separate TestPlutusBatch6V3Builtins class (array builtins are Batch 6 per Plutus Core spec)
• Tests will gracefully skip with clear message until PV11 is available: "Array builtins require PV11+ (currently not supported in cardano-node-tests)"

Script Source:

• Generated from plutus-scripts-e2e PR [QA] - Update stake pool parameters (margin, pledge, tax) #12 (yura/add-array-builtin-scripts branch)
• All three validators are minting policies (standard pattern for testing pure computational builtins)
• Validators use hardcoded test data internally (no external redeemer parameters needed)

Why Minting Policies:
Array builtins are pure computational functions that don't require transaction context, datum management, or UTxO state. Minting policies provide:

• Simpler setup (1-step vs 3-step for spending validators)
• Better test isolation (no UTxO state between tests)
• Easier parallelization
• Consistency with 58 other V3 builtin tests

Changes

Test Scripts (Binary)

• succeedingIndexArrayPolicyScriptV3.plutus (299 bytes) - Tests indexArray arr 2 == 3 for [1,2,3,4,5]
• succeedingLengthOfArrayPolicyScriptV3.plutus (286 bytes) - Tests lengthOfArray arr == 3 for [10,20,30]
• succeedingListToArrayPolicyScriptV3.plutus (360 bytes) - Tests conversion + boundary access for [100,200,300,400]

Script Definitions (plutus_common.py:467-493)

• Added 3 PlutusScriptData definitions with PV11 requirement documented
• Execution costs initialized to (0, 0) placeholders (will be updated after PV11 testing)
• Created SUCCEEDING_MINTING_ARRAY_SCRIPTS_V3 tuple for parametrized testing

Test Class (test_mint_build.py:190-317)

• TestPlutusBatch6V3Builtins - New test class with comprehensive docstring explaining PV11 blocker
• skip_bootstrap fixture checks for PV11+ (currently skips all tests)
• test_array_builtins - Parametrized test covering all 3 array scripts
• Follows same pattern as Batch 5: minting transaction, collateral management, token verification
• Marked as @pytest.mark.smoke for quick validation once PV11 available

How to Test

Current Status: Tests will skip until PV11 support added. To verify test infrastructure:

# Verify tests are present and properly skip
pytest -k "array_builtins" cardano_node_tests/tests/tests_plutus_v3/test_mint_build.py -v

# Expected output:
# SKIPPED [1] Array builtins require PV11+ (currently not supported in cardano-node-tests)

After PV11 Support Available:

1. Ensure cluster is running PV11+ with updated PlutusV3 cost model:

   source ./prepare_test_env.sh conway
   ./dev_workdir/conway_fast/start-cluster
   # Verify: cardano-cli query protocol-parameters | jq '.protocolVersion.major'
   # Should show: 11

2. Run array builtin tests:

   pytest -k "array_builtins" cardano_node_tests/tests/tests_plutus_v3/test_mint_build.py -v

3. Extract execution costs from test output:

   • Look for actual per_time and per_space values in test logs
   • Update plutus_common.py:472,479,486 with measured costs
   • Verify costs reflect CIP-0138 performance expectations:
     • indexArray: O(1) constant time/memory
     • lengthOfArray: O(1) constant time/memory
     • listToArray: O(n) linear time/memory

4. Run full smoke test suite:

   pytest -m "smoke" cardano_node_tests/tests/tests_plutus_v3/test_mint_build.py

Expected Results:

• All 3 array builtin tests pass
• Tokens successfully minted using array policies
• Execution costs within ±15% tolerance of updated values

Performance Expectations (CIP-0138)

Builtin	Complexity	Expected Cost Pattern
indexArray	O(1)	Constant, ~500K per_time
lengthOfArray	O(1)	Constant, ~300K per_time
listToArray	O(n)	Linear in array size

Dependencies

• Blocker: PV11 support in cardano-node-tests (expected early next week)
• Upstream: plutus-scripts-e2e PR [QA] - Update stake pool parameters (margin, pledge, tax) #12 (merged/ready)
• Related: plutus-private#1920 (array builtin validators implementation)

Author's Checklist

• Self-reviewed code
• Followed established test patterns (Batch 5 builtins)
• Created separate test class for Batch 6 (correct organization)
• Documented PV11 requirement prominently
• Added graceful skip logic until PV11 available
• Used minting policies (appropriate for pure builtin testing)
• Marked as smoke tests for quick validation
• Added execution cost measurements (blocked until PV11)
• Verified tests pass on PV11 cluster (blocked until PV11)

Post-PV11 Follow-up

Once PV11 support is available:

1. Run tests on PV11 cluster
2. Update execution costs with measured values
3. Verify costs match CIP-0138 performance expectations
4. Consider adding failing test variants (out-of-bounds, empty arrays, etc.)

Closes #3227

[kwxm]

Please don't merge this just yet! I've been working on some other tests that will conflict with this a little. I'll open a PR shortly.