diff --git a/keyserver/jest-setup.js b/keyserver/jest-setup.js
new file mode 100644
--- /dev/null
+++ b/keyserver/jest-setup.js
@@ -0,0 +1,8 @@
+// @flow
+
+import crypto from 'crypto';
+
+// crypto.webcrypto was introduced in Node 15.10.0.
+// It is not defined in Flow so we need a cast
+// eslint-disable-next-line no-undef -- "global is not defined"
+global.crypto = (crypto: any).webcrypto;
diff --git a/keyserver/package.json b/keyserver/package.json
--- a/keyserver/package.json
+++ b/keyserver/package.json
@@ -100,6 +100,9 @@
     },
     "transformIgnorePatterns": [
       "/node_modules/(?!@babel/runtime)"
+    ],
+    "setupFiles": [
+      "<rootDir>/jest-setup.js"
     ]
   }
 }
diff --git a/keyserver/src/utils/olm-utils.test.js b/keyserver/src/utils/olm-utils.test.js
--- a/keyserver/src/utils/olm-utils.test.js
+++ b/keyserver/src/utils/olm-utils.test.js
@@ -8,6 +8,13 @@
   it('should get Olm Utility', async () => {
     await olm.init();
     const utility = getOlmUtility();
-    expect(utility).not.toBe(undefined);
+    expect(utility).toBeDefined();
+  });
+  it('should be able to generate and return prekey', async () => {
+    await olm.init();
+    const account = new olm.Account();
+    account.create();
+    account.generate_prekey();
+    expect(account.prekey()).toBeDefined();
   });
 });
diff --git a/web/olm/olm.test.js b/web/olm/olm.test.js
--- a/web/olm/olm.test.js
+++ b/web/olm/olm.test.js
@@ -8,4 +8,11 @@
     const account = new olm.Account();
     expect(account).not.toBe(undefined);
   });
+  it('should be able to generate and return prekey', async () => {
+    await olm.init();
+    const account = new olm.Account();
+    account.create();
+    account.generate_prekey();
+    expect(account.prekey()).not.toBe(undefined);
+  });
 });