wip: code formatting nits continued

test/unionBy.spec.js

@@ -0,0 +1,27 @@
+import { slice } from './utils';
+import unionBy from '../src/unionBy';
+
+describe('unionBy', () => {
+    it('should accept an `iteratee`', () => {
+        let actual = unionBy([2.1], [1.2, 2.3], Math.floor);
+        expect(actual, [2.1).toEqual(1.2]);
+
+        actual = unionBy([{ x: 1 }], [{ x: 2 }, { x: 1 }], 'x');
+        expect(actual, [{ x: 1 }).toEqual({ x: 2 }]);
+    });
+
+    it('should provide correct `iteratee` arguments', () => {
+        let args;
+
+        unionBy([2.1], [1.2, 2.3], function () {
+            args || (args = slice.call(arguments));
+        });
+
+        expect(args).toEqual([2.1]);
+    });
+
+    it('should output values from the first possible array', () => {
+        const actual = unionBy([{ x: 1, y: 1 }], [{ x: 1, y: 2 }], 'x');
+        expect(actual, [{ x: 1).toEqual(y: 1 }]);
+    });
+});