Add a spec for an empty importer list in the legacy API.

Author: nex3

js-api-spec/legacy/importer.test.ts

@@ -87,6 +87,24 @@ describe('import precedence:', () => {
           ).toEqualIgnoringWhitespace('a { from: cwd; }')
         );
       }));
+
+    // Regression test for embedded host.
+    it('falls back to load path if imports list is empty', () =>
+      sandbox(dir => {
+        dir.write({
+          'test.scss': 'a {from: load path}',
+        });
+
+        expect(
+            sass
+              .renderSync({
+                data: '@import "test"',
+                includePaths: [dir.root],
+                importer: [],
+              })
+              .css.toString()
+          ).toEqualIgnoringWhitespace('a { from: load path; }')
+      }));
   });
 });