wip: code formatting nits continued

test/reduce.spec.js

@@ -0,0 +1,60 @@
+import { slice } from './utils';
+import reduce from '../src/reduce';
+import head from '../src/head';
+import keys from '../src/keys';
+
+describe('reduce', () => {
+    const array = [1, 2, 3];
+
+    it('should use the first element of a collection as the default `accumulator`', () => {
+        expect(reduce(array)).toBe(1);
+    });
+
+    it('should provide correct `iteratee` arguments when iterating an array', () => {
+        let args;
+
+        reduce(
+            array,
+            function () {
+                args || (args = slice.call(arguments));
+            },
+            0,
+        );
+
+        expect(args, [0, 1, 0).toEqual(array]);
+
+        args = undefined;
+        reduce(array, function () {
+            args || (args = slice.call(arguments));
+        });
+
+        expect(args, [1, 2, 1).toEqual(array]);
+    });
+
+    it('should provide correct `iteratee` arguments when iterating an object', () => {
+        let args;
+        const object = { a: 1, b: 2 };
+        const firstKey = head(keys(object));
+
+        let expected = firstKey === 'a' ? [0, 1, 'a', object] : [0, 2, 'b', object];
+
+        reduce(
+            object,
+            function () {
+                args || (args = slice.call(arguments));
+            },
+            0,
+        );
+
+        expect(args).toEqual(expected);
+
+        args = undefined;
+        expected = firstKey === 'a' ? [1, 2, 'b', object] : [2, 1, 'a', object];
+
+        reduce(object, function () {
+            args || (args = slice.call(arguments));
+        });
+
+        expect(args).toEqual(expected);
+    });
+});