added test

Author: benwest

test/fixtures/whitespace-in-var-declaration.css

@@ -0,0 +1,9 @@
+:root {
+    --foo: 1px;
+}
+
+.bar {
+    width: var( --foo );
+    height: var( --foo);
+    margin-top: var(--foo );
+}

test/fixtures/whitespace-in-var-declaration.expected.css

@@ -0,0 +1,5 @@
+.bar {
+    width: 1px;
+    height: 1px;
+    margin-top: 1px;
+}

test/test.js

@@ -257,6 +257,8 @@ describe('postcss-css-variables', function() {
 		test('should not mangle outer function parentheses', 'nested-inside-other-func');
 	});
 
+	test('should accept whitespace in var() declarations', 'whitespace-in-var-declaration' )
+
 	it('should not parse malformed var() declarations', function() {
 		return expect(testPlugin(
 			'./test/fixtures/malformed-variable-usage.css',