Add range tests demonstrating boundaries (#40)

* Add range tests demonstrating boundaries

Signed-off-by: Mark Moir <[email protected]>

* Review: spelling

Signed-off-by: Mark Moir <[email protected]>

---------

Signed-off-by: Mark Moir <[email protected]>

tests/range.rs

@@ -0,0 +1,148 @@
+use blsful::inner_types::*;
+use credx::claim::{ClaimType, HashedClaim, NumberClaim, RevocationClaim};
+use credx::credential::{ClaimSchema, CredentialSchema};
+use credx::issuer::Issuer;
+use credx::knox::bbs::BbsScheme;
+use credx::presentation::{Presentation, PresentationSchema};
+use credx::statement::{CommitmentStatement, RangeStatement, SignatureStatement};
+use credx::{random_string, CredxResult};
+use indexmap::indexmap;
+use maplit::btreeset;
+use rand::{thread_rng, RngCore};
+
+macro_rules! range_test_with {
+    ($name: ident, $val:expr, $lower:expr, $upper:expr, $expected_to_fail:expr) => {
+        #[test]
+        fn $name() -> CredxResult<()> {
+            let _ = env_logger::builder().is_test(true).try_init();
+            let res = test_range_proof_works($val, $lower, $upper, $expected_to_fail);
+            assert!(res.is_ok(), "{:?}", res);
+            Ok(())
+        }
+    };
+}
+
+// These tests are expected to pass (expected_to_fail argument is false)
+range_test_with!(in_range_from_flow_test, 30303, Some(0), Some(44829), false);
+range_test_with!(in_range_min, 0, Some(0), Some(isize::MAX), false);
+range_test_with!(
+    in_range_max_explicit,
+    isize::MAX,
+    Some(0),
+    Some(isize::MAX),
+    false
+);
+range_test_with!(in_range_max_implicit, isize::MAX, Some(0), None, false);
+
+// These tests are expected to fail (expected_to_fail argument is true)
+range_test_with!(out_of_range_below, 0, Some(1), Some(isize::MAX), true);
+range_test_with!(out_of_range_above, 1001, Some(0), Some(1000), true);
+
+fn test_range_proof_works(
+    val: isize,
+    lower: Option<isize>,
+    upper: Option<isize>,
+    expected_to_fail: bool,
+) -> Result<(), String> {
+    const LABEL: &str = "Test Schema";
+    const DESCRIPTION: &str = "This is a test presentation schema";
+    const CRED_ID: &str = "91742856-6eda-45fb-a709-d22ebb5ec8a5";
+    let schema_claims = [
+        ClaimSchema {
+            claim_type: ClaimType::Revocation,
+            label: "identifier".to_string(),
+            print_friendly: false,
+            validators: vec![],
+        },
+        ClaimSchema {
+            claim_type: ClaimType::Hashed,
+            label: "name".to_string(),
+            print_friendly: true,
+            validators: vec![],
+        },
+        ClaimSchema {
+            claim_type: ClaimType::Hashed,
+            label: "address".to_string(),
+            print_friendly: true,
+            validators: vec![],
+        },
+        ClaimSchema {
+            claim_type: ClaimType::Number,
+            label: "age".to_string(),
+            print_friendly: true,
+            validators: vec![],
+        },
+    ];
+    let cred_schema = CredentialSchema::new(Some(LABEL), Some(DESCRIPTION), &[], &schema_claims)
+        .map_err(|e| format!("unexpected, CredentialSchema::new failed {e:?}"))?;
+
+    let (issuer_public, mut issuer) = Issuer::<BbsScheme>::new(&cred_schema);
+
+    let credential = issuer
+        .sign_credential(&[
+            RevocationClaim::from(CRED_ID).into(),
+            HashedClaim::from("John Doe").into(),
+            HashedClaim::from("P Sherman 42 Wallaby Way Sydney").into(),
+            NumberClaim::from(val).into(),
+        ])
+        .map_err(|e| format!("unexpected, sign credential failed {e:?}"))?;
+
+    let sig_st = SignatureStatement {
+        disclosed: btreeset! {"name".to_string()},
+        id: random_string(16, rand::thread_rng()),
+        issuer: issuer_public.clone(),
+    };
+    let comm_st = CommitmentStatement {
+        id: random_string(16, rand::thread_rng()),
+        reference_id: sig_st.id.clone(),
+        message_generator: G1Projective::hash::<ExpandMsgXmd<sha2::Sha256>>(
+            b"message generator",
+            b"BLS12381G1_XMD:SHA-256_SSWU_RO_",
+        ),
+        blinder_generator: G1Projective::hash::<ExpandMsgXmd<sha2::Sha256>>(
+            b"blinder generator",
+            b"BLS12381G1_XMD:SHA-256_SSWU_RO_",
+        ),
+        claim: 3,
+    };
+    let range_st = RangeStatement {
+        id: random_string(16, thread_rng()),
+        reference_id: comm_st.id.clone(),
+        signature_id: sig_st.id.clone(),
+        claim: 3,
+        lower,
+        upper,
+    };
+
+    let mut nonce = [0u8; 16];
+    thread_rng().fill_bytes(&mut nonce);
+
+    let credentials = indexmap! { sig_st.id.clone() => credential.credential.into() };
+    let presentation_schema =
+        PresentationSchema::new(&[sig_st.into(), comm_st.into(), range_st.into()]);
+    match Presentation::create(&credentials, &presentation_schema, &nonce) {
+        Err(e) => {
+            if expected_to_fail {
+                Ok(())
+            } else {
+                Err(format!("create presentation failed: {e:?}"))
+            }
+        }
+        Ok(presentation) => match presentation.verify(&presentation_schema, &nonce) {
+            Err(e) => {
+                if expected_to_fail {
+                    Ok(())
+                } else {
+                    Err(format!("verify presentation failed: {e:?}"))
+                }
+            }
+            Ok(_) => {
+                if expected_to_fail {
+                    Err("verification passed, but was expected to fail".to_string())
+                } else {
+                    Ok(())
+                }
+            }
+        },
+    }
+}