Compact Core:testing Debugging

Testing & Debugging

Essential guidance for testing Compact contracts, debugging common errors, and understanding compiler/runtime error messages.

Common Errors Quick Reference

Debugging Decision Tree

Error during compilation?
├── "potential witness-value disclosure"
│   └── See: references/error-messages.md#disclosure-errors
├── "type mismatch" or "cannot convert"
│   └── See: references/error-messages.md#type-errors
├── "unbounded loop" or "bounds must be constant"
│   └── See: references/error-messages.md#loop-errors
└── Other compilation error
    └── See: references/error-messages.md

Error during proof generation?
├── "assert failed" or "constraint failed"
│   └── Check assertion conditions and witness values
├── "proof generation failed"
│   └── Verify witness functions return expected types
└── "overflow" or "division by zero"
    └── Check arithmetic bounds

Testing Approaches

Unit Testing Circuits

import { TestContext } from '@midnight-ntwrk/compact-testing';

describe('MyContract', () => {
    let ctx: TestContext;

    beforeEach(async () => {
        ctx = await TestContext.create('my_contract.compact');
    });

    it('should process valid input', async () => {
        const result = await ctx.call('process', [42n]);
        expect(result.success).toBe(true);
    });
});

Witness Mocking

const mockWitness = {
    get_secret: () => BigInt('12345'),
    get_balance: () => BigInt(1000)
};

const result = await ctx.call('transfer', [recipient], mockWitness);

State Verification

// Read ledger state after circuit execution
const balance = await ctx.ledger.get('balances', userKey);
expect(balance).toBe(expectedBalance);

Common Pitfalls

References

• Error Messages - Complete error reference with solutions
• Testing Strategy - Testing approaches and best practices
• Common Pitfalls - Frequent mistakes and how to avoid them

Examples

• Test Setup - TypeScript test harness configuration
• Mock Witnesses - Witness mocking patterns