Add failing tests for #58

#58
"Comparing object with "hasOwnProperty" keys fails"

Author: anko

src/added/index.test.js

@@ -105,5 +105,13 @@ describe('.addedDiff', () => {
         expect(addedDiff(lhs, rhs)).toEqual({ date: new Date('2016') });
       });
     });
+
+    describe('object with non-function hasOwnProperty property', () => {
+      test('can represent the property in diff despite it being part of Object.prototype', () => {
+        const lhs = {};
+        const rhs = { hasOwnProperty: true };
+        expect(addedDiff(lhs, rhs)).toEqual({ hasOwnProperty: true });
+      });
+    });
   });
 });

src/deleted/index.test.js

@@ -107,5 +107,13 @@ describe('.deletedDiff', () => {
         expect(deletedDiff({ date: new Date('2016') }, rhs)).toEqual({ date: undefined });
       });
     });
+
+    describe('object with non-function hasOwnProperty property', () => {
+      test('can represent the property in diff despite it being part of Object.prototype', () => {
+        const lhs = { hasOwnProperty: true };
+        const rhs = {};
+        expect(deletedDiff(lhs, rhs)).toEqual({ hasOwnProperty: undefined });
+      });
+    });
   });
 });

src/updated/index.test.js

@@ -147,5 +147,13 @@ describe('.updatedDiff', () => {
         expect(updatedDiff(lhs, rhs)).toEqual({ date: new Date('2017') });
       });
     });
+
+    describe('object with non-function hasOwnProperty property', () => {
+      test('can represent the property in diff despite it being part of Object.prototype', () => {
+        const lhs = { hasOwnProperty: false };
+        const rhs = { hasOwnProperty: true };
+        expect(updatedDiff(lhs, rhs)).toEqual({ hasOwnProperty: true });
+      });
+    });
   });
 });