Add test for missing branch

Author: mattphillips

src/diff/index.test.js

@@ -97,6 +97,11 @@ describe('.diff', () => {
     describe('date', () => {
       const lhs = new Date('2016');
       const rhs = new Date('2017');
+
+      test('returns empty object when dates are equal', () => {
+        expect(diff(new Date('2016'), new Date('2016'))).toEqual({});
+      });
+
       test('returns right hand side date when updated', () => {
         expect(diff({ date: lhs }, { date: rhs })).toEqual({ date: rhs });
         expect(diff([lhs], [rhs])).toEqual({ 0: rhs });

src/updated/index.test.js

@@ -97,5 +97,11 @@ describe('.updatedDiff', () => {
         expect(updatedDiff([new Date('2016')], [new Date('2017')])).toEqual({ 0: new Date('2017') });
       });
     });
+
+    describe('date', () => {
+      test('returns empty object when dates are equal', () => {
+        expect(updatedDiff(new Date('2016'), new Date('2016'))).toEqual({});
+      });
+    });
   });
 });