rewrite mapreduce upsert tests with async/await

tests/unit/test.mapreduce.js

@@ -6,63 +6,51 @@ var upsert = PouchDB.utils.upsert;
 var utils = PouchDB.utils.mapReduceUtils;
 
 describe('test.mapreduce.js-upsert', function () {
-  it('should throw an error if the doc errors', function () {
-    return upsert({
-      get: function () {
-        return Promise.reject(new Error('a fake error!'));
-      }
-    }, 'foo')
-    .then(function () {
+  it('should throw an error if the doc errors', async function () {
+    try {
+      await upsert({
+        get: () => Promise.reject(new Error('a fake error!')),
+      }, 'foo');
+
       should.fail("Expected promise to be rejected");
-    })
-    .catch(function (err) {
+    } catch (err) {
       err.message.should.equal("a fake error!");
-    });
+    }
   });
-  it('should fulfill if the diff returns false', function () {
-    return upsert({
-      get: function () {
-        return Promise.resolve({ _rev: 'xyz' });
-      }
-    }, 'foo', function () {
-      return false;
-    }).then(function (res) {
-      res.updated.should.equal(false);
-      res.rev.should.equal('xyz');
-    });
+
+  it('should fulfill if the diff returns false', async function () {
+    const res = await upsert({
+      get: () => Promise.resolve({ _rev: 'xyz' }),
+    }, 'foo', () => false
+  );
+
+    res.updated.should.equal(false);
+    res.rev.should.equal('xyz');
   });
-  it('should put if get throws 404', function () {
-    return upsert({
-      get: function () {
-        return Promise.reject({ status: 404 });
-      },
-      put: function () {
-        return Promise.resolve({ rev: 'abc' });
-      }
-    }, 'foo', function () {
-      return { difference: "something" };
-    }).then(function (res) {
-      res.updated.should.equal(true);
-      res.rev.should.equal('abc');
-    });
+
+  it('should put if get throws 404', async function () {
+    const res = await upsert({
+      get: () => Promise.reject({ status: 404 }),
+      put: () => Promise.resolve({ rev: 'abc' }),
+    }, 'foo', () => ({ difference: "something" })
+    );
+
+    res.updated.should.equal(true);
+    res.rev.should.equal('abc');
   });
-  it('should error if it can\'t put', function () {
-    return upsert({
-      get: function () {
-        return Promise.resolve({ _rev: 'xyz' });
-      },
-      put: function () {
-        return Promise.reject(new Error('falala'));
-      }
-    }, 'foo', function () {
-      return { difference: "something" };
-    })
-    .then(function () {
+
+  it('should error if it can\'t put', async function () {
+    try {
+      await upsert({
+        get: () => Promise.resolve({ _rev: 'xyz' }),
+        put: () => Promise.reject(new Error('falala')),
+      }, 'foo', () => ({ difference: "something" })
+      );
+
       should.fail("Expected promise to be rejected");
-    })
-    .catch(function (err) {
+    } catch (err) {
       err.message.should.equal("falala");
-    });
+    }
   });
 });