fix: stricter @import tolerance (#593)

* Added failed test for @import-normalize

* Fixed import handling not matching import like constructs.

* Made tolerant for null match on urls inside import

* Added request test case

lib/processCss.js

@@ -42,12 +42,12 @@ var parserPlugin = postcss.plugin("css-loader-parser", function(options) {
 		}
 
 		if(options.import) {
-			css.walkAtRules(/import/i, function(rule) {
+			css.walkAtRules(/^import$/i, function(rule) {
 				var values = Tokenizer.parseValues(rule.params);
 				var url = values.nodes[0].nodes[0];
-				if(url.type === "url") {
+				if(url && url.type === "url") {
 					url = url.url;
-				} else if(url.type === "string") {
+				} else if(url && url.type === "string") {
 					url = url.value;
 				} else throw rule.error("Unexpected format " + rule.params);
 				if (!url.replace(/\s/g, '').length) {

test/importTest.js

@@ -1,6 +1,10 @@
 /*globals describe */
 
-var test = require("./helpers").test;
+var assert = require('assert');
+
+var helpers = require("./helpers");
+var test = helpers.test;
+var testError = helpers.testError;
 
 describe("import", function() {
 	test("import", "@import url(test.css);\n.class { a: b c d; }", [
@@ -66,4 +70,16 @@ describe("import", function() {
 	test("import disabled", "@import url(test.css);\n.class { a: b c d; }", [
 		[1, "@import url(test.css);\n.class { a: b c d; }", ""]
 	], "?-import");
-});
+	test("@import-normalize left untouched", "@import-normalize;", [
+		[1, "@import-normalize;", ""]
+	]);
+	testError("@import without url", "@import;", function(err) {
+		assert.equal(err.message, [
+			'Unexpected format  (1:1)',
+			'',
+			'> 1 | @import;',
+			'    | ^',
+			'',
+		].join('\n'))
+	})
+})