Add functional test for sass imports via package.json sass property

Author: David Ellingsworth

fixtures/css/sass_package_import.scss

@@ -0,0 +1,7 @@
+// There seems to be an issue with the sass-loader and prefixing
+// aliased directories with a tilde. The following line is how
+// this import should look and works for node_modules.
+// @import '~lib/test-pkg';
+
+// Importing without the tilde seems to work for webpack aliases
+@import 'lib/test-pkg';

fixtures/lib/test-pkg/css/sass_entry.scss

@@ -0,0 +1,5 @@
+$content:'Sass entrypoint';
+
+body {
+    content:$content;
+}

fixtures/lib/test-pkg/js/javascript_entry.js

@@ -0,0 +1,3 @@
+"use strict";
+
+document.write("JavaScript entrypoint");

fixtures/lib/test-pkg/package.json

@@ -0,0 +1,10 @@
+{
+    "name":"@symfony/webpack-encore-test-pkg",
+    "description": "This is a test package for use by functional tests which use packages.",
+    "author": {
+        "name": "David Ellingsworth",
+        "email": "david@desource.org"
+    },
+    "main":"js/javascript_entry.js",
+    "sass":"css/sass_entry.scss"
+}

test/functional.js

@@ -1972,5 +1972,22 @@ module.exports = {
                 });
             });
         });
+
+        describe('Package entrypoint imports', () => {
+            it('Import via "sass" package property', (done) => {
+                const config = createWebpackConfig('web/build', 'dev');
+
+                config.setPublicPath('/build');
+                config.addAliases({
+                    lib:path.resolve('./lib')
+                });
+                config.enableSassLoader();
+                config.addStyleEntry('sass', './css/sass_package_import.scss');
+
+                testSetup.runWebpack(config, () => {
+                    done();
+                })
+            });
+        });
     });
 });