add hw2

node_modules/khroma/test/methods/opacify.js

@@ -0,0 +1,25 @@
+
+/* IMPORT */
+
+import {describe} from 'fava';
+import {opacify} from '../../dist/index.js';
+
+/* MAIN */
+
+describe ( 'opacify', it => {
+
+  it ( 'increases the opacity channel of the color', t => {
+
+    const tests = [
+      [['#000000', 1], '#000000'],
+      [['rgba(0, 0, 0, 0.5)', 0.5], '#000000'],
+      [['rgba(0, 0, 0, 0.5)', 0.1], 'rgba(0, 0, 0, 0.6)']
+    ];
+
+    tests.forEach ( ([ args, output ]) => {
+      t.is ( opacify ( ...args ), output );
+    });
+
+  });
+
+});