Add tests for error cases in did-resolver.spec.ts (#561)

* Add tests for error cases in did-resolver.spec.ts

This commit adds new tests in did-resolver.spec.ts to cover some of the previously uncovered error-related branching paths.

This commit contributes partly to issue #136.

Based on the output of `npm run test:node` before vs. after this commit, the `% Branch` is now increased by 9.66 percentage points, and the `% Stmt` and `% Lines` by 3.29 percentage points.

Before:
```
did-resolver.ts |   87.91 |    78.57 |   66.66 |   87.91
```

After:
```
did-resolver.ts |    91.2 |    88.23 |   66.66 |    91.2 |
```

* Add tests for error cases in did-resolver.spec.ts

This commit adds new tests in did-resolver.spec.ts to cover some of the previously uncovered error-related branching paths.

This commit contributes partly to issue #136.

Based on the output of `npm run test:node` before vs. after this commit, the `% Branch` is now increased by 9.66 percentage points, and the `% Stmt` and `% Lines` by 3.29 percentage points.

Before:
```
did-resolver.ts |   87.91 |    78.57 |   66.66 |   87.91
```

After:
```
did-resolver.ts |   92.34 |    94.11 |   66.66 |   92.34 |
```

* Add tests for error cases in did-resolver.spec.ts

This commit adds new tests in did-resolver.spec.ts to cover some of the previously uncovered error-related branching paths.

This commit contributes partly to issue #136.

Based on the output of `npm run test:node` before vs. after this commit, the `% Branch` is now increased by 9.66 percentage points, and the `% Stmt` and `% Lines` by 3.29 percentage points.

Before:
```
did-resolver.ts |   87.91 |    78.57 |   66.66 |   87.91
```

After:
```
did-resolver.ts |   92.34 |    94.11 |   66.66 |   92.34 |
```

* Arrange new Did related error codes alphabetically

* Use a different code for DidNotString

README.md

@@ -48,7 +48,7 @@ Here's to a thrilling Hacktoberfest voyage with us! 🎉
 # Decentralized Web Node (DWN) SDK <!-- omit in toc -->
 
 Code Coverage
-![Statements](https://img.shields.io/badge/statements-98.35%25-brightgreen.svg?style=flat) ![Branches](https://img.shields.io/badge/branches-95.14%25-brightgreen.svg?style=flat) ![Functions](https://img.shields.io/badge/functions-95.73%25-brightgreen.svg?style=flat) ![Lines](https://img.shields.io/badge/lines-98.35%25-brightgreen.svg?style=flat)
+![Statements](https://img.shields.io/badge/statements-98.46%25-brightgreen.svg?style=flat) ![Branches](https://img.shields.io/badge/branches-95.29%25-brightgreen.svg?style=flat) ![Functions](https://img.shields.io/badge/functions-95.73%25-brightgreen.svg?style=flat) ![Lines](https://img.shields.io/badge/lines-98.46%25-brightgreen.svg?style=flat)
 
 - [Introduction](#introduction)
 - [Installation](#installation)

src/core/dwn-error.ts

@@ -15,6 +15,10 @@ export class DwnError extends Error {
 export enum DwnErrorCode {
   AuthenticateJwsMissing = 'AuthenticateJwsMissing',
   AuthorizationUnknownAuthor = 'AuthorizationUnknownAuthor',
+  DidMethodNotSupported = 'DidMethodNotSupported',
+  DidNotString = 'DidNotString',
+  DidNotValid = 'DidNotValid',
+  DidResolutionFailed = 'DidResolutionFailed',
   GeneralJwsVerifierInvalidSignature = 'GeneralJwsVerifierInvalidSignature',
   GrantAuthorizationGrantExpired = 'GrantAuthorizationGrantExpired',
   GrantAuthorizationGrantMissing = 'GrantAuthorizationGrantMissing',

src/did/did-resolver.ts

@@ -5,6 +5,7 @@ import { Did } from './did.js';
 import { DidIonResolver } from './did-ion-resolver.js';
 import { DidKeyResolver } from './did-key-resolver.js';
 import { MemoryCache } from '../utils/memory-cache.js';
+import { DwnError, DwnErrorCode } from '../core/dwn-error.js';
 
 /**
  * A DID resolver that by default supports `did:key` and `did:ion` DIDs.
@@ -49,7 +50,7 @@ export class DidResolver {
     const didResolver = this.didResolvers.get(didMethod);
 
     if (!didResolver) {
-      throw new Error(`${didMethod} DID method not supported`);
+      throw new DwnError(DwnErrorCode.DidMethodNotSupported, `${didMethod} DID method not supported`);
     }
 
     // use cached result if exists
@@ -66,7 +67,7 @@ export class DidResolver {
       let errMsg = `Failed to resolve DID ${did}.`;
       errMsg += error ? ` Error: ${error}` : '';
 
-      throw new Error(errMsg);
+      throw new DwnError(DwnErrorCode.DidResolutionFailed, errMsg);
     }
 
     return resolutionResult;

src/did/did.ts

@@ -1,3 +1,5 @@
+import { DwnError, DwnErrorCode } from '../core/dwn-error.js';
+
 /**
  * DID related operations.
  */
@@ -16,13 +18,13 @@ export class Did {
    */
   public static validate(did: unknown): void {
     if (typeof did !== 'string') {
-      throw new Error(`DID is not string: ${did}`);
+      throw new DwnError(DwnErrorCode.DidNotString, `DID is not string: ${did}`);
     }
 
     // eslint-disable-next-line
     const didRegex= /^did:([a-z0-9]+):((?:(?:[a-zA-Z0-9._-]|(?:%[0-9a-fA-F]{2}))*:)*((?:[a-zA-Z0-9._-]|(?:%[0-9a-fA-F]{2}))+))((;[a-zA-Z0-9_.:%-]+=[a-zA-Z0-9_.:%-]*)*)(\/[^#?]*)?([?][^#]*)?(#.*)?$/;
     if (!didRegex.test(did)) {
-      throw new TypeError(`DID is not a valid DID: ${did}`);
+      throw new DwnError(DwnErrorCode.DidNotValid, `DID is not a valid DID: ${did}`);
     }
   }
 

tests/did/did-resolver.spec.ts

@@ -4,6 +4,7 @@ import chai, { expect } from 'chai';
 
 import { DidIonResolver } from '../../src/did/did-ion-resolver.js';
 import { DidResolver } from '../../src/did/did-resolver.js';
+import { DwnErrorCode } from '../../src/core/dwn-error.js';
 
 // extends chai to test promises
 chai.use(chaiAsPromised);
@@ -32,4 +33,63 @@ describe('DidResolver', () => {
     sinon.assert.calledTwice(cacheGetSpy); // should try to fetch from cache both times
     sinon.assert.calledOnce(ionDidResolveSpy); // should only resolve using ION resolver once (the first time)
   });
+
+  it('should throw error when invalid DID is used', async () => {
+    const did = 'blah';
+    const didIonResolver = new DidIonResolver();
+    const didResolver = new DidResolver([didIonResolver]);
+
+    await expect(didResolver.resolve(did)).to.eventually.be.rejected.and.has.property('code', DwnErrorCode.DidNotValid);
+  });
+
+  it('should throw error when unsupported DID method is used', async () => {
+    const did = 'did:foo:EiClkZMDxPKqC9c-umQfTkR8vvZ9JPhl_xLDI9Nfk38w5w';
+    const didIonResolver = new DidIonResolver();
+    const didResolver = new DidResolver([didIonResolver]);
+
+    await expect(didResolver.resolve(did)).to.eventually.be.rejected.and.has.property('code', DwnErrorCode.DidMethodNotSupported);
+  });
+
+  it('should throw error when resolution fails due to error in didResolutionMetadata', async () => {
+    const did = 'did:ion:EiClkZMDxPKqC9c-umQfTkR8vvZ9JPhl_xLDI9Nfk38w5w';
+    const didIonResolver = new DidIonResolver('unusedResolutionEndpoint');
+    const didResolver = new DidResolver([didIonResolver]);
+
+    const mockResolution = {
+      didDocument           : 'any' as any,
+      didResolutionMetadata : { error: 'some error' },
+      didDocumentMetadata   : 'any' as any
+    };
+
+    const ionDidResolveSpy = sinon.stub(didIonResolver, 'resolve').resolves(mockResolution);
+    const cacheGetSpy = sinon.spy(didResolver['cache'], 'get');
+
+    await expect(didResolver.resolve(did)).to.eventually.be.rejected.and.has.property('code', DwnErrorCode.DidResolutionFailed);
+
+    sinon.assert.calledOnce(cacheGetSpy);
+    sinon.assert.calledOnce(ionDidResolveSpy);
+
+  });
+
+  it('should throw error when resolution fails due to undefined didDocument', async () => {
+    const did = 'did:ion:EiClkZMDxPKqC9c-umQfTkR8vvZ9JPhl_xLDI9Nfk38w5w';
+    const didIonResolver = new DidIonResolver('unusedResolutionEndpoint');
+    const didResolver = new DidResolver([didIonResolver]);
+
+    const mockResolution = {
+      didDocument           : undefined,
+      didResolutionMetadata : 'any' as any,
+      didDocumentMetadata   : 'any' as any
+    };
+
+    const ionDidResolveSpy = sinon.stub(didIonResolver, 'resolve').resolves(mockResolution);
+    const cacheGetSpy = sinon.spy(didResolver['cache'], 'get');
+
+    await expect(didResolver.resolve(did)).to.eventually.be.rejected.and.has.property('code', DwnErrorCode.DidResolutionFailed);
+
+    sinon.assert.calledOnce(cacheGetSpy);
+    sinon.assert.calledOnce(ionDidResolveSpy);
+
+  });
+
 });

tests/did/did.spec.ts

@@ -3,6 +3,8 @@ import chai, { expect } from 'chai';
 
 import { Did } from '../../src/did/did.js';
 
+import { DwnError } from '../../src/core/dwn-error.js';
+
 // extends chai to test promises
 chai.use(chaiAsPromised);
 
@@ -15,6 +17,6 @@ describe('Did.validate', () => {
 
   it('should fail validation for valid DIDs', () => {
     expect(() => Did.validate(null)).to.throw(Error);
-    expect(() => Did.validate('did:123456789abcdefghijk')).to.throw(Error);
+    expect(() => Did.validate('did:123456789abcdefghijk')).to.throw(DwnError);
   });
 });