diff --git a/test/sync-async.js b/test/sync-async.js
new file mode 100644
index 000000000..b7036c58b
--- /dev/null
+++ b/test/sync-async.js
@@ -0,0 +1,253 @@
+'use strict'
+/* global describe, it, beforeEach, afterEach */
+
+const expect = require('chai').expect
+const checkOutput = require('./helpers/utils').checkOutput
+const isPromise = require('../lib/is-promise')
+let yargs
+
+describe('yargs sync/async tests', () => {
+  beforeEach(() => {
+    yargs = require('../')
+  })
+
+  afterEach(() => {
+    delete require.cache[require.resolve('../')]
+  })
+
+  describe('parse', () => {
+    it('should return argv when sync handler returns', () => {
+      expectReturns(['cmd'], () => {
+        return yargs(['cmd'])
+          .command('cmd', 'description', () => { }, () => { })
+          .parse()
+      })
+    })
+
+    it('should throw when syntax is incorrect and handler sync', () => {
+      expectThrows(/Unknown argument: unknown-cmd/, () => {
+        return yargs(['unknown-cmd'])
+          .command('cmd', 'description', () => { }, () => { })
+          .strict()
+          .exitProcess(false)
+          .parse()
+      })
+    })
+
+    it('should throw when sync handler throws', () => {
+      expectThrows(/handler error/, () => {
+        return yargs(['cmd'])
+          .command('cmd', 'description', () => { }, () => {
+            throw new Error('handler error')
+          })
+          .exitProcess(false)
+          .parse()
+      })
+    })
+
+    it('should resolve argv when async handler resolves', (done) => {
+      expectResolves(done, ['cmd'], () => {
+        return yargs(['cmd'])
+          .command('cmd', 'description', () => { }, () => Promise(
+            (resolve) => process.nextTick(resolve)
+          ))
+          .parse()
+      })
+    })
+
+    it('should throw when syntax is incorrect and handler is async', () => {
+      expectThrows(/Unknown argument: unknown-cmd/, () => {
+        return yargs(['unknown-cmd'])
+          .command('cmd', 'description', () => { }, () => Promise(
+            (resolve) => process.nextTick(resolve)
+          ))
+          .strict()
+          .exitProcess(false)
+          .parse()
+      })
+    })
+
+    it('should reject when async handler rejects', (done) => {
+      expectRejects(done, /handler error/, () => {
+        return yargs(['cmd'])
+          .command('cmd', 'description', () => { }, () => Promise(
+            (_, reject) => process.nextTick(reject, 'handler error')
+          ))
+          .strict()
+          .exitProcess(false)
+          .parse()
+      })
+    })
+  })
+
+  describe('parseAsync', () => {
+    it('should resolve argv when sync handler returns', (done) => {
+      expectResolves(done, ['cmd'], () => {
+        return yargs(['cmd'])
+          .command('cmd', 'description', () => { }, () => { })
+          .parseAsync()
+      })
+    })
+
+    it('should reject when syntax is incorrect and handler sync', (done) => {
+      expectRejects(done, /Unknown argument: unknown-cmd/, () => {
+        return yargs(['unknown-cmd'])
+          .command('cmd', 'description', () => { }, () => { })
+          .strict()
+          .exitProcess(false)
+          .parseAsync()
+      })
+    })
+
+    it('should reject when sync command handler throws', (done) => {
+      expectRejects(done, /handler error/, () => {
+        return yargs(['cmd'])
+          .command('cmd', 'description', () => { }, () => {
+            throw new Error('handler error')
+          })
+          .exitProcess(false)
+          .parseAsync()
+      })
+    })
+
+    it('should resolve argv when async handler resolves', (done) => {
+      expectResolves(done, ['cmd'], () => {
+        return yargs(['cmd'])
+          .command('cmd', 'description', () => { }, () => Promise(
+            (resolve) => process.nextTick(resolve)
+          ))
+          .parseAsync()
+      })
+    })
+
+    it('should reject when syntax is incorrect and handler async', (done) => {
+      expectRejects(done, /Unknown argument: unknown-cmd/, () => {
+        return yargs(['unknown-cmd'])
+          .command('cmd', 'description', () => { }, () => Promise(
+            (resolve) => process.nextTick(resolve)
+          ))
+          .strict()
+          .exitProcess(false)
+          .parseAsync()
+      })
+    })
+
+    it('should reject when async handler rejects', (done) => {
+      expectRejects(done, /handler error/, () => {
+        return yargs(['cmd'])
+          .command('cmd', 'description', () => { }, () => Promise(
+            (_, reject) => process.nextTick(reject, 'handler error')
+          ))
+          .exitProcess(false)
+          .parseAsync()
+      })
+    })
+  })
+
+  describe('parseSync', () => {
+    it('should return argv when handler is sync', () => {
+      expectReturns(['cmd'], () => {
+        return yargs(['cmd'])
+          .command('cmd', 'description', () => { }, () => { })
+          .parseSync()
+      })
+    })
+
+    it('should throw when syntax is incorrect and handler sync', () => {
+      expectThrows(/Unknown argument: unknown-cmd/, () => {
+        return yargs(['unknown-cmd'])
+          .command('cmd', 'description', () => { }, () => { })
+          .strict()
+          .exitProcess(false)
+          .parseSync()
+      })
+    })
+
+    it('should throw when sync command handler throws', () => {
+      expectThrows(/handler error/, () => {
+        return yargs(['cmd'])
+          .command('cmd', 'description', () => { }, () => {
+            throw new Error('handler error')
+          })
+          .exitProcess(false)
+          .parseSync()
+      })
+    })
+
+    it('should throw when async handler resolves', () => {
+      expectThrows(/asynchronous parsing results/, () => {
+        return yargs(['cmd'])
+          .command('cmd', 'description', () => { }, () => Promise(
+            (resolve) => process.nextTick(resolve)
+          ))
+          .exitProcess(false)
+          .parseSync()
+      })
+    })
+
+    it('should throw when syntax is incorrect and handler is async', () => {
+      expectThrows(/Unknown argument: unknown-cmd/, () => {
+        return yargs(['unknown-cmd'])
+          .command('cmd', 'description', () => { }, () => Promise(
+            (resolve) => process.nextTick(resolve)
+          ))
+          .strict()
+          .exitProcess(false)
+          .parseSync()
+      })
+    })
+
+    it('should throw when async handler rejects', () => {
+      expectThrows(/asynchronous parsing results/, () => {
+        return yargs(['cmd'])
+          .command('cmd', 'description', () => { }, () => Promise(
+            (_, reject) => process.nextTick(reject)
+          ))
+          .exitProcess(false)
+          .parseSync()
+      })
+    })
+  })
+})
+
+function expectReturns (positionals, parse) {
+  checkOutput(() => {
+    const argv = parse()
+    expect(isPromise(argv)).to.equal(false)
+    expect(argv._).to.deep.equal(positionals)
+  })
+}
+
+function expectThrows (message, parse) {
+  checkOutput(() => {
+    expect(parse).to.throw(message)
+  })
+}
+
+function expectResolves (done, positionals, parse) {
+  checkOutput(() => {
+    const argvPromise = parse()
+    expect(isPromise(argvPromise)).to.equal(true)
+    argvPromise.then(
+      (argv) => {
+        expect(argv._).to.deep.equal(positionals)
+        done()
+      },
+      () => done('the promise should have been resolved')
+    )
+  })
+}
+
+function expectRejects (done, message, parse) {
+  checkOutput(() => {
+    const argvPromise = parse()
+    expect(isPromise(argvPromise)).to.equal(true)
+    argvPromise.then(
+      () => done('the promise should have been rejected'),
+      (err) => {
+        expect(err.message).to.match(message)
+        done()
+      }
+    )
+  })
+}