add eq test

Cargo.toml

@@ -56,3 +56,7 @@ path = "src/mint.rs"
 name = "spend"
 path = "src/spend.rs"
 
+[[bin]]
+name = "eq"
+path = "src/eq.rs"
+

src/eq.rs

@@ -0,0 +1,76 @@
+use bellman::{
+    gadgets::{
+        boolean::{AllocatedBit, Boolean},
+        multipack,
+        Assignment,
+        num
+    },
+    groth16, Circuit, ConstraintSystem, SynthesisError,
+};
+use bls12_381::Bls12;
+use group::Curve;
+use rand::rngs::OsRng;
+
+pub const CRH_IVK_PERSONALIZATION: &[u8; 8] = b"Zcashivk";
+
+struct MyCircuit {
+    value: Option<bls12_381::Scalar>,
+}
+
+impl Circuit<bls12_381::Scalar> for MyCircuit {
+    fn synthesize<CS: ConstraintSystem<bls12_381::Scalar>>(
+        self,
+        cs: &mut CS,
+    ) -> Result<(), SynthesisError> {
+        let x = num::AllocatedNum::alloc(cs.namespace(|| "conditional anchor"), || {
+            Ok(*self.value.get()?)
+        })?;
+
+        cs.enforce(
+            || "conditionally enforce correct root",
+            |lc| lc + x.get_variable(),
+            |lc| lc + CS::one(),
+            |lc| lc + x.get_variable(),
+        );
+
+        Ok(())
+    }
+}
+
+fn main() {
+    use std::time::Instant;
+
+    let start = Instant::now();
+    // Create parameters for our circuit. In a production deployment these would
+    // be generated securely using a multiparty computation.
+    let params = {
+        let c = MyCircuit { value: None };
+        groth16::generate_random_parameters::<Bls12, _, _>(c, &mut OsRng).unwrap()
+    };
+    println!("Setup: [{:?}]", start.elapsed());
+
+    // Prepare the verification key (for proof verification).
+    let pvk = groth16::prepare_verifying_key(&params.vk);
+
+    // Pick a preimage and compute its hash.
+    let value = bls12_381::Scalar::one();
+
+    // Create an instance of our circuit (with the preimage as a witness).
+    let c = MyCircuit {
+        value: Some(value),
+    };
+
+    let start = Instant::now();
+    // Create a Groth16 proof with our parameters.
+    let proof = groth16::create_random_proof(c, &params, &mut OsRng).unwrap();
+    println!("Prove: [{:?}]", start.elapsed());
+
+    let start = Instant::now();
+
+    let mut public_input = [bls12_381::Scalar::zero(); 0];
+
+    let start = Instant::now();
+    // Check the proof!
+    assert!(groth16::verify_proof(&pvk, &proof, &public_input).is_ok());
+    println!("Verify: [{:?}]", start.elapsed());
+}