[contract] Add 3 Tests to liquidity_tests.rs (Part 2)

[Olowodarey]

📋 Overview

Expand test coverage for the liquidity module by adding 3 new tests (Part 2 of 2).

✅ Tasks

• Add 3 new test functions to contract/tests/liquidity_tests.rs
• Follow existing test patterns and helper functions
• Verify all tests pass

🧪 New Tests (3 total)

Test 1: Multiple LPs Fee Distribution

#[test]
fn test_multiple_lps_fee_distribution() {
    // Multiple users add liquidity
    // Swaps occur (fees collected)
    // Verify fees are distributed proportionally to LP tokens
}

Test 2: Slippage Protection

#[test]
fn test_swap_slippage_protection() {
    // Add liquidity
    // Try swap with min_amount_out too high
    // Should fail with slippage exceeded error
}

Test 3: Liquidity After Market Resolution

#[test]
fn test_liquidity_after_market_resolution() {
    // Add liquidity
    // Resolve market
    // Verify LPs can still withdraw
    // Verify no new swaps allowed
}

🔍 Verification

• All 3 tests written
• All tests pass
• Tests follow existing patterns
• No clippy warnings

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