diff --git a/test/parallel/test-crypto-certificate.js b/test/parallel/test-crypto-certificate.js
index 1dfb2c73b0eca5..8dba530fc54a45 100644
--- a/test/parallel/test-crypto-certificate.js
+++ b/test/parallel/test-crypto-certificate.js
@@ -37,3 +37,6 @@ assert.strictEqual(certificate.exportChallenge(spkacFail), '');
 function stripLineEndings(obj) {
   return obj.replace(/\n/g, '');
 }
+
+// direct call Certificate() should return instance
+assert(crypto.Certificate() instanceof crypto.Certificate);
diff --git a/test/parallel/test-crypto-sign-verify.js b/test/parallel/test-crypto-sign-verify.js
index 6df41409f0e6c1..b4ef8296282b7f 100644
--- a/test/parallel/test-crypto-sign-verify.js
+++ b/test/parallel/test-crypto-sign-verify.js
@@ -70,3 +70,10 @@ var keyPem = fs.readFileSync(common.fixturesDir + '/test_key.pem', 'ascii');
   verified = verStream.verify(certPem, s3);
   assert.strictEqual(verified, true, 'sign and verify (stream)');
 }
+
+// Test throws exception when key options is null
+{
+  assert.throws(() => {
+    crypto.createSign('RSA-SHA1').update('Test123').sign(null, 'base64');
+  }, /^Error: No key provided to sign$/);
+}