From 65f2cb590162b5d6afd98d9a439f0d03eef56664 Mon Sep 17 00:00:00 2001
From: Julien Fraichot <julien.fraichot@hyland.com>
Date: Tue, 3 Dec 2024 14:58:15 +0100
Subject: [PATCH] fix(DataIntegrity): respect error contract for external
 consumers

---
 src/index.ts                                  | 19 +++++++++----------
 .../data-integrity-proof-support.test.ts      | 18 ++++++++++++------
 2 files changed, 21 insertions(+), 16 deletions(-)

diff --git a/src/index.ts b/src/index.ts
index 6beacb7..cbea2ab 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -137,17 +137,16 @@ export class LDMerkleProof2019 extends LinkedDataProof {
     let verified: boolean;
     let error: string = '';
 
-    if (this.proof.proofPurpose) {
-      if (this.proof.proofPurpose !== this.proofPurpose) {
-        throw new Error(`Invalid proof purpose. Expected ${this.proofPurpose} but received ${this.proof.proofPurpose}`);
-      }
-
-      if (this.issuer && !this.issuer[this.proofPurpose]?.includes(this.proof.verificationMethod)) {
-        throw new Error(`The verification method ${this.proof.verificationMethod} is not allowed for the proof purpose ${this.proofPurpose}`);
-      }
-    }
-
     try {
+      if (this.proof.proofPurpose) {
+        if (this.proof.proofPurpose !== this.proofPurpose) {
+          throw new Error(`Invalid proof purpose. Expected ${this.proofPurpose} but received ${this.proof.proofPurpose}`);
+        }
+
+        if (this.issuer && !this.issuer[this.proofPurpose]?.includes(this.proof.verificationMethod)) {
+          throw new Error(`The verification method ${this.proof.verificationMethod} is not allowed for the proof purpose ${this.proofPurpose}`);
+        }
+      }
       await this.verifyProcess(this.proofVerificationProcess);
       if (verifyIdentity) {
         await this.verifyIdentity();
diff --git a/tests/verification/data-integrity-proof-support.test.ts b/tests/verification/data-integrity-proof-support.test.ts
index a82beb2..315bc17 100644
--- a/tests/verification/data-integrity-proof-support.test.ts
+++ b/tests/verification/data-integrity-proof-support.test.ts
@@ -27,9 +27,12 @@ describe('given the document is signed following the DataIntegrityProof spec', f
         proofPurpose: 'authentication'
       });
 
-      await expect(async () => {
-        await instance.verifyProof();
-      }).rejects.toThrow('Invalid proof purpose. Expected authentication but received assertionMethod');
+      const result = await instance.verifyProof();
+      expect(result).toEqual({
+        verified: false,
+        verificationMethod: null,
+        error: 'Invalid proof purpose. Expected authentication but received assertionMethod'
+      });
     });
   });
 
@@ -45,9 +48,12 @@ describe('given the document is signed following the DataIntegrityProof spec', f
         issuer: fixtureIssuerProfile
       });
 
-      await expect(async () => {
-        await instance.verifyProof();
-      }).rejects.toThrow('The verification method https://www.blockcerts.org/samples/3.0/issuer-blockcerts.json#key-1 is not allowed for the proof purpose authentication');
+      const result = await instance.verifyProof();
+      expect(result).toEqual({
+        verified: false,
+        verificationMethod: null,
+        error: 'The verification method https://www.blockcerts.org/samples/3.0/issuer-blockcerts.json#key-1 is not allowed for the proof purpose authentication'
+      });
     });
   });
 });