Testing the Coin Flip

Pre-Alpha Disclaimer: This is an early pre-alpha release for exploring the SDK and starting development only. There is no real encryption — all data is completely public and stored as plaintext on-chain. Do not submit any sensitive or real data. Encryption keys and the trust model are not final; do not rely on any encryption guarantees or key material until mainnet. All interfaces, APIs, and data formats are subject to change without notice. The Solana program and all on-chain data will be wiped periodically and everything will be deleted when we transition to Encrypt Alpha 1. This software is provided “as is” without warranty of any kind; use is entirely at your own risk and dWallet Labs assumes no liability for any damages arising from its use.

What you’ll learn

Unit testing the FHE graph with mock compute
How the mock evaluator works
What each test case validates

Graph unit tests

The #[encrypt_fn] macro generates a function that returns the graph bytecode. You can test the graph logic without deploying to Solana by running it through a mock evaluator:

#![allow(unused)]
fn main() {
#[test]
fn xor_same_side_b_wins() {
    let r = run_mock(
        coin_flip_graph,
        &[0, 0],
        &[FheType::EUint64, FheType::EUint64],
    );
    assert_eq!(r[0], 0, "0^0=0 -> side_b wins");
}

#[test]
fn xor_diff_side_a_wins() {
    let r = run_mock(
        coin_flip_graph,
        &[0, 1],
        &[FheType::EUint64, FheType::EUint64],
    );
    assert_eq!(r[0], 1, "0^1=1 -> side_a wins");
}
}

The run_mock helper parses the graph bytecode and evaluates each node using mock digest encoding/decoding. This simulates exactly what the executor does, but with plaintext values encoded as mock identifiers.

Test matrix

Inputs	XOR	Winner	Test
0, 0	0	Side B	`xor_same_side_b_wins`
0, 1	1	Side A	`xor_diff_side_a_wins`
1, 1	0	Side B	`xor_both_one_side_b_wins`
1, 0	1	Side A	`xor_one_zero_side_a_wins`

Graph shape test

#![allow(unused)]
fn main() {
#[test]
fn graph_shape() {
    let d = coin_flip_graph();
    let pg = parse_graph(&d).unwrap();
    assert_eq!(pg.header().num_inputs(), 2, "commit_a + commit_b");
    assert_eq!(pg.header().num_outputs(), 1, "single flip result");
}
}

Validates that the compiled graph has exactly 2 inputs and 1 output. This catches accidental changes to the graph signature.

Running tests

# Unit tests only (no SBF build needed)
cargo test -p encrypt-coin-flip-anchor

# Or run all example tests
just test-examples

E2E tests

The e2e/ directory contains integration tests that deploy the program to a local validator (LiteSVM or solana-program-test), run the full flow (create game, play, decrypt, reveal), and verify the winner gets paid. These require the SBF binary:

just build-sbf-examples
just test-examples-litesvm

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