diff --git a/test/claim-sub.tests.js b/test/claim-sub.tests.js
new file mode 100644
index 0000000..cd7ffac
--- /dev/null
+++ b/test/claim-sub.tests.js
@@ -0,0 +1,107 @@
+'use strict';
+
+const jwt = require('../');
+const expect = require('chai').expect;
+const util = require('util');
+
+function signWithSubject(payload, subject) {
+  const options = {algorithm: 'none'};
+  if (subject !== undefined) {
+    options.subject = subject;
+  }
+  return jwt.sign(payload, undefined, options);
+}
+
+describe('subject', function() {
+  describe('`jwt.sign` "subject" option validation', function () {
+    [
+      true,
+      false,
+      null,
+      -1,
+      0,
+      1,
+      -1.1,
+      1.1,
+      -Infinity,
+      Infinity,
+      NaN,
+      [],
+      ['foo'],
+      {},
+      {foo: 'bar'},
+    ].forEach((subject) => {
+      it(`should error with with value ${util.inspect(subject)}`, function () {
+        expect(() => signWithSubject({}, subject)).to.throw('"subject" must be a string');
+      });
+    });
+
+    // undefined needs special treatment because {} is not the same as {subject: undefined}
+    it('should error with with value undefined', function () {
+      expect(() => jwt.sign({}, undefined, {subject: undefined, algorithm: 'none'})).to.throw(
+        '"subject" must be a string'
+      );
+    });
+
+    it('should error when "sub" is in payload', function () {
+      expect(() => signWithSubject({sub: 'bar'}, 'foo')).to.throw(
+        'Bad "options.subject" option. The payload already has an "sub" property.'
+      );
+    });
+
+
+    it('should error with a string payload', function () {
+      expect(() => signWithSubject('a string payload', 'foo')).to.throw(
+        'invalid subject option for string payload'
+      );
+    });
+
+    it('should error with a Buffer payload', function () {
+      expect(() => signWithSubject(new Buffer('a Buffer payload'), 'foo')).to.throw(
+        'invalid subject option for object payload'
+      );
+    });
+  });
+
+  describe('when signing and verifying a token with "subject" option', function () {
+    it('should verify with a string "subject"', function () {
+      const token = signWithSubject({}, 'foo');
+      const decoded = jwt.decode(token);
+      const verified = jwt.verify(token, undefined, {subject: 'foo'});
+      expect(decoded).to.deep.equal(verified);
+      expect(decoded.sub).to.equal('foo');
+    });
+
+    it('should verify with a string "sub"', function () {
+      const token = signWithSubject({sub: 'foo'});
+      const decoded = jwt.decode(token);
+      const verified = jwt.verify(token, undefined, {subject: 'foo'});
+      expect(decoded).to.deep.equal(verified);
+      expect(decoded.sub).to.equal('foo');
+    });
+
+    it('should not verify "sub" if "verify.subject" option not provided', function() {
+      const token = signWithSubject({sub: 'foo'});
+      const decoded = jwt.decode(token);
+      const verified = jwt.verify(token, undefined);
+      expect(decoded).to.deep.equal(verified);
+      expect(decoded.sub).to.equal('foo');
+    });
+
+    it('should error if "sub" does not match "verify.subject" option', function() {
+      const token = signWithSubject({sub: 'foo'});
+      expect(() => jwt.verify(token, undefined, {subject: 'bar'})).to.throw(
+        jwt.JsonWebTokenError,
+        'jwt subject invalid. expected: bar'
+      );
+    });
+
+    it('should error without "sub" and with "verify.subject" option', function() {
+      const token = signWithSubject({});
+      expect(() => jwt.verify(token, undefined, {subject: 'foo'})).to.throw(
+        jwt.JsonWebTokenError,
+        'jwt subject invalid. expected: foo'
+      );
+    });
+  });
+});
diff --git a/test/jwt.asymmetric_signing.tests.js b/test/jwt.asymmetric_signing.tests.js
index 27a5212..6951b95 100644
--- a/test/jwt.asymmetric_signing.tests.js
+++ b/test/jwt.asymmetric_signing.tests.js
@@ -157,42 +157,6 @@ describe('Asymmetric Algorithms', function(){
         });
       });
 
-      describe('when signing a token with subject', function () {
-        var token = jwt.sign({ foo: 'bar' }, priv, { algorithm: algorithm, subject: 'subject' });
-
-        it('should check subject', function (done) {
-          jwt.verify(token, pub, { subject: 'subject' }, function (err, decoded) {
-            assert.isNotNull(decoded);
-            assert.isNull(err);
-            done();
-          });
-        });
-
-        it('should throw when invalid subject', function (done) {
-          jwt.verify(token, pub, { subject: 'wrongSubject' }, function (err, decoded) {
-            assert.isUndefined(decoded);
-            assert.isNotNull(err);
-            assert.equal(err.name, 'JsonWebTokenError');
-            assert.instanceOf(err, jwt.JsonWebTokenError);
-            done();
-          });
-        });
-      });
-
-      describe('when signing a token without subject', function () {
-        var token = jwt.sign({ foo: 'bar' }, priv, { algorithm: algorithm });
-
-        it('should check subject', function (done) {
-          jwt.verify(token, pub, { subject: 'subject' }, function (err, decoded) {
-            assert.isUndefined(decoded);
-            assert.isNotNull(err);
-            assert.equal(err.name, 'JsonWebTokenError');
-            assert.instanceOf(err, jwt.JsonWebTokenError);
-            done();
-          });
-        });
-      });
-
       describe('when signing a token with jwt id', function () {
         var token = jwt.sign({ foo: 'bar' }, priv, { algorithm: algorithm, jwtid: 'jwtid' });
 
diff --git a/test/schema.tests.js b/test/schema.tests.js
index 30c817a..77592d6 100644
--- a/test/schema.tests.js
+++ b/test/schema.tests.js
@@ -51,13 +51,6 @@ describe('schema', function() {
       sign({issuer: 'foo'});
     });
 
-    it('should validate subject', function () {
-      expect(function () {
-        sign({ subject: 10 });
-      }).to.throw(/"subject" must be a string/);
-      sign({subject: 'foo'});
-    });
-
     it('should validate noTimestamp', function () {
       expect(function () {
         sign({ noTimestamp: 10 });