Parallel testing

[erhant]

Consider the following test (of a logical OR gate):

await circuit.expectPass({ in: [0, 0] }, { out: 0 });
await circuit.expectPass({ in: [0, 1] }, { out: 0 });
await circuit.expectPass({ in: [1, 0] }, { out: 0 });
await circuit.expectPass({ in: [1, 1] }, { out: 1 });

If we were to use Promise.all for these, we get errors. Need to dive deeper into why that happens.