diff --git a/lib/package.json b/lib/package.json
index 806c0410..f1c22aae 100644
--- a/lib/package.json
+++ b/lib/package.json
@@ -49,9 +49,9 @@
     "license-check": "license-checker-rseidelsohn --production --onlyAllow 'Apache-2.0; BSD; CC-BY-4.0; ISC; MIT'",
     "lint": "eslint ./src/**/*.ts ./tdf3/**/*.ts ./tests/**/*.ts",
     "prepack": "npm run build",
-    "test": "npm run build && npm run test:wtr && npm run test:mocha && npm run test:browser && npm run coverage:merge",
+    "test": "npm run build && npm run test:mocha && npm run test:wtr && npm run test:browser && npm run coverage:merge",
     "test:browser": "rm -rf tests/mocha/dist && node tests/server.cjs & npx webpack --config webpack.test.config.cjs && npx karma start karma.conf.cjs; node tests/stopServer.cjs",
-    "test:mocha": "node tests/server.cjs & c8 --exclude=\"dist/web/tests/\" --exclude=\"dist/web/tdf3/src/utils/aws-lib-storage/\"  --exclude=\"dist/web/tests/**/*\" --report-dir=./coverage/mocha mocha 'dist/web/tests/mocha/**/*.spec.js' --file tests/mocha/setup.js ; npx c8 report --reporter=json --report-dir=./coverage/mocha; node tests/stopServer.cjs",
+    "test:mocha": "node tests/server.cjs & trap \"node tests/stopServer.cjs\" EXIT; c8 --exclude=\"dist/web/tests/\" --exclude=\"dist/web/tdf3/src/utils/aws-lib-storage/\"  --exclude=\"dist/web/tests/**/*\" --report-dir=./coverage/mocha mocha 'dist/web/tests/mocha/**/*.spec.js' --file tests/mocha/setup.js && npx c8 report --reporter=json --report-dir=./coverage/mocha",
     "test:wtr": "web-test-runner",
     "watch": "(trap 'kill 0' SIGINT; npm run build && (npm run build:watch & npm run test -- --watch))"
   },
diff --git a/lib/tdf3/src/models/attribute-set.ts b/lib/tdf3/src/models/attribute-set.ts
index b1faeedf..f01fa292 100644
--- a/lib/tdf3/src/models/attribute-set.ts
+++ b/lib/tdf3/src/models/attribute-set.ts
@@ -27,7 +27,15 @@ const ATTRIBUTE_OBJECT_SCHEMA: JSONSchemaType<AttributeObject> = {
   additionalProperties: false,
 };
 
-const validator = new Ajv.default();
+const validator = (() => {
+  try {
+    //@ts-expect-error: Ajv not a constructor
+    return new Ajv();
+  } catch (e) {
+    console.log(e);
+  }
+  return new Ajv.default();
+})();
 
 export class AttributeSet {
   attributes: AttributeObject[];
@@ -148,11 +156,13 @@ export class AttributeSet {
    * @return {Object} - Decrypted and added attribute object
    */
   addJwtAttribute(jwtAttribute: { jwt: string }) {
-    const { jwt: attrJwt } = jwtAttribute;
+    const attrJwt = jwtAttribute?.jwt;
     // Can't verify the JWT because the client does not have the easPublicKey,
     // but the contents of the JWT can be decoded.
-    const attrObjPayload = decodeJwt(attrJwt);
-    if (!attrObjPayload) return null;
+    const attrObjPayload = attrJwt && decodeJwt(attrJwt);
+    if (!attrObjPayload) {
+      return null;
+    }
     // JWT payloads contain many things, incluing .iat and .exp. This
     // extraneous material should be stripped away before adding the
     // attribute to the attributeSet.
diff --git a/lib/tests/mocha/encrypt-decrypt.spec.ts b/lib/tests/mocha/encrypt-decrypt.spec.ts
index eaa99b08..518dbb72 100644
--- a/lib/tests/mocha/encrypt-decrypt.spec.ts
+++ b/lib/tests/mocha/encrypt-decrypt.spec.ts
@@ -18,58 +18,61 @@ describe('encrypt decrypt test', async function () {
   const kasUrl = `http://localhost:4000/`;
   const kasPublicKey = await TDF.extractPemFromKeyString(Mocks.kasPublicKey);
 
-  const sandbox = createSandbox();
-  const tdf1 = TDF.create({ cryptoService });
-  sandbox.replace(
-    TDF,
-    'create',
-    sandbox.fake(() => tdf1)
-  );
-  sandbox.spy(tdf1, '_generateManifest');
-  sandbox.stub(tdf1, 'unwrapKey').callsFake(async () => {
-    // @ts-ignore
-    const keyInfo = tdf1._generateManifest.lastCall.args[0];
-    return {
-      reconstructedKeyBinary: keyInfo.unwrappedKeyBinary as Binary,
-      metadata: undefined,
-    };
-  });
-
   it('encrypt-decrypt stream source happy path', async function () {
-    const client = new Client.Client({
-      kasEndpoint: kasUrl,
-      kasPublicKey,
-      keypair: { publicKey: Mocks.entityPublicKey, privateKey: Mocks.entityPrivateKey },
-      clientId: 'id',
-      authProvider,
-    });
+    const sandbox = createSandbox();
+    try {
+      const tdf1 = TDF.create({ cryptoService });
+      sandbox.replace(
+        TDF,
+        'create',
+        sandbox.fake(() => tdf1)
+      );
+      sandbox.spy(tdf1, '_generateManifest');
+      sandbox.stub(tdf1, 'unwrapKey').callsFake(async () => {
+        // @ts-ignore
+        const keyInfo = tdf1._generateManifest.lastCall.args[0];
+        return {
+          reconstructedKeyBinary: keyInfo.unwrappedKeyBinary as Binary,
+          metadata: undefined,
+        };
+      });
+      const client = new Client.Client({
+        kasEndpoint: kasUrl,
+        kasPublicKey,
+        keypair: { publicKey: Mocks.entityPublicKey, privateKey: Mocks.entityPrivateKey },
+        clientId: 'id',
+        authProvider,
+      });
 
-    const eo = await Mocks.getEntityObject();
-    const scope = Mocks.getScope();
+      const eo = await Mocks.getEntityObject();
+      const scope = Mocks.getScope();
 
-    const encryptedStream = await client.encrypt({
-      eo,
-      metadata: Mocks.getMetadataObject(),
-      offline: true,
-      scope,
-      source: new ReadableStream({
-        start(controller) {
-          controller.enqueue(new TextEncoder().encode(expectedVal));
-          controller.close();
-        },
-      }),
-    });
+      const encryptedStream = await client.encrypt({
+        eo,
+        metadata: Mocks.getMetadataObject(),
+        offline: true,
+        scope,
+        source: new ReadableStream({
+          start(controller) {
+            controller.enqueue(new TextEncoder().encode(expectedVal));
+            controller.close();
+          },
+        }),
+      });
 
-    const decryptStream = await client.decrypt({
-      eo,
-      source: {
-        type: 'stream',
-        location: encryptedStream.stream,
-      },
-    });
+      const decryptStream = await client.decrypt({
+        eo,
+        source: {
+          type: 'stream',
+          location: encryptedStream.stream,
+        },
+      });
 
-    const { value: decryptedText } = await decryptStream.stream.getReader().read();
+      const { value: decryptedText } = await decryptStream.stream.getReader().read();
 
-    assert.equal(new TextDecoder().decode(decryptedText), expectedVal);
+      assert.equal(new TextDecoder().decode(decryptedText), expectedVal);
+    } finally {
+      sandbox.restore();
+    }
   });
 });
diff --git a/lib/tests/mocha/unit/attribute-set.spec.ts b/lib/tests/mocha/unit/attribute-set.spec.ts
index 4369c423..87a24d59 100644
--- a/lib/tests/mocha/unit/attribute-set.spec.ts
+++ b/lib/tests/mocha/unit/attribute-set.spec.ts
@@ -209,4 +209,22 @@ describe('AttributeSet', function () {
     const aSet = new AttributeSet();
     assert.deepEqual(aSet.get('unknown URL'), null);
   });
+
+  it('empty jwt attribute', async () => {
+    const aSet = new AttributeSet();
+    // @ts-expect-error invalid value
+    aSet.addJwtAttribute({});
+    assert.equal(aSet.attributes.length, 0);
+    assert.deepEqual(aSet.getDefault(), null);
+  });
+
+  it('simplest jwt attribute', async () => {
+    const aSet = new AttributeSet();
+    const attribute = 'https://example.com/attr/test-case/value/bar';
+    const jwtAttr = await Mocks.createJwtAttribute({ attribute });
+    aSet.addJwtAttribute(jwtAttr);
+
+    const expected = Mocks.createAttribute({ attribute });
+    assert.include(aSet.get(attribute), expected);
+  });
 });
diff --git a/lib/tests/mocha/unit/tdf.spec.ts b/lib/tests/mocha/unit/tdf.spec.ts
index cbbb3b1d..17a545f3 100644
--- a/lib/tests/mocha/unit/tdf.spec.ts
+++ b/lib/tests/mocha/unit/tdf.spec.ts
@@ -51,7 +51,8 @@ describe('TDF', () => {
   });
 
   it('allowedKases', () => {
-    const actual = TDF.create({ allowedKases: ['https://local.virtru.com'], cryptoService });
+    const cfg = { allowedKases: ['https://local.virtru.com'], cryptoService };
+    const actual = TDF.create(cfg);
     expect(actual.allowedKases).to.contain('https://local.virtru.com');
   });