Add color scheme query

Author: CodingItWrong

src/queries/colorScheme.js

@@ -0,0 +1,9 @@
+const buildQuery = require('./buildQuery');
+
+const colorScheme = buildQuery(
+  requiredScheme =>
+    ({colorScheme}) =>
+      colorScheme === requiredScheme
+);
+
+module.exports = {colorScheme};

src/queries/colorScheme.test.js

@@ -0,0 +1,21 @@
+const {colorScheme} = require('./colorScheme');
+
+describe('colorScheme', () => {
+  describe('the first element of the returned array, the predicate', () => {
+    describe('when color scheme matches', () => {
+      it('returns true', () => {
+        const [predicate] = colorScheme('dark', {});
+        const returnValue = predicate({colorScheme: 'dark'});
+        expect(returnValue).toEqual(true);
+      });
+    });
+
+    describe('when color scheme does not match', () => {
+      it('returns false', () => {
+        const [predicate] = colorScheme('dark', {});
+        const returnValue = predicate({colorScheme: 'light'});
+        expect(returnValue).toEqual(false);
+      });
+    });
+  });
+});