[FIX] Support absolute import paths in less files (#107)

Absolute paths in imports are now correctly passed through to the filesystem without making them relative to the current directory.

lib/index.js

@@ -150,7 +150,14 @@ Builder.prototype.build = function(options) {
 	}
 
 	function fileHandler(file, currentFileInfo, handleDataAndCallCallback, callback) {
-		const pathname = path.posix.join(currentFileInfo.currentDirectory, file);
+		let pathname;
+
+		// support absolute paths such as "/resources/my/base.less"
+		if (path.posix.isAbsolute(file)) {
+			pathname = path.posix.normalize(file);
+		} else {
+			pathname = path.posix.join(currentFileInfo.currentDirectory, file);
+		}
 
 		that.fileUtils.readFile(pathname, options.rootPaths).then(function(result) {
 			if (!result) {

test/expected/libraries/scopes/comments/lib3/comments/themes/bar/library-RTL.css

@@ -0,0 +1,19 @@
+/**
+ * This is a sample comment!
+ */
+.myRule1 {
+  /**
+	* This is a sample comment inside a rule
+	* with a different color value!
+	*/
+  color: #ffffff;
+}
+b {
+  color: green;
+}
+a {
+  color: green;
+}
+html {
+  color: green;
+}

test/expected/libraries/scopes/comments/lib3/comments/themes/bar/library.css

@@ -0,0 +1,19 @@
+/**
+ * This is a sample comment!
+ */
+.myRule1 {
+  /**
+	* This is a sample comment inside a rule
+	* with a different color value!
+	*/
+  color: #ffffff;
+}
+b {
+  color: green;
+}
+a {
+  color: green;
+}
+html {
+  color: green;
+}

test/fixtures/libraries/scopes/comments/lib3/comments/themes/bar/library.source.less

@@ -0,0 +1,15 @@
+/**
+ * This is a sample comment!
+ */
+
+.myRule1 {
+	/**
+	* This is a sample comment inside a rule
+	* with a different color value!
+	*/
+	color: #ffffff;
+}
+
+@import "/lib3/comments/themes/other/sub/my.less";
+@import "./my2.less";
+@import "../my3.less";

test/fixtures/libraries/scopes/comments/lib3/comments/themes/bar/my2.less

@@ -0,0 +1,3 @@
+a {
+  color: green;
+}

test/fixtures/libraries/scopes/comments/lib3/comments/themes/my3.less

@@ -0,0 +1,3 @@
+html {
+  color: green;
+}

test/fixtures/libraries/scopes/comments/lib3/comments/themes/other/sub/my.less

@@ -0,0 +1,3 @@
+b {
+  color: green;
+}

test/test-custom-fs.js

@@ -18,6 +18,7 @@
 const assert = require("assert");
 const readFile = require("./common/helper").readFile;
 const fs = require("fs");
+const path = require("path");
 
 // tested module
 const Builder = require("../").Builder;
@@ -72,5 +73,43 @@ describe("(custom fs) CSS Scoping of", function() {
 				assert.equal(statCalls, 19, "fs.stat should have been called 19 times");
 			});
 		});
+
+
+		it("should return same CSS for bar with absolute import paths", function() {
+			const readFileCalls = [];
+
+
+			let statCalls = 0;
+
+			return new Builder({
+				fs: {
+					readFile: function(...args) {
+						readFileCalls.push(args[0]);
+						return fs.readFile(...args);
+					},
+					stat: function(...args) {
+						statCalls++;
+						return fs.stat(...args);
+					}
+				}
+			}).build({
+				lessInputPath: "lib3/comments/themes/bar/library.source.less",
+				rootPaths: [
+					"test/fixtures/libraries/scopes/comments"
+				]
+			}).then(function(result) {
+				assert.equal(result.css, readFile("test/expected/libraries/scopes/comments/lib3/comments/themes/bar/library.css"), "CSS scoping should be correctly generated");
+				assert.equal(result.cssRtl, readFile("test/expected/libraries/scopes/comments/lib3/comments/themes/bar/library-RTL.css"), "Rtl CSS scoping should be correctly generated");
+
+				const basePath = path.join("test/fixtures/libraries/scopes/comments/lib3/comments", "themes");
+				assert.deepEqual(readFileCalls, [
+					path.join(basePath, "bar/library.source.less"),
+					path.join(basePath, "other/sub/my.less"),
+					path.join(basePath, "bar/my2.less"),
+					path.join(basePath, "my3.less")
+				], "fs.readFile should have been called with import paths");
+				assert.equal(statCalls, 10, "fs.stat should have been called 19 times");
+			});
+		});
 	});
 });