added a test for the cssi format explicity

Author: geelen

test/cssi/interchange-format/colors.css

@@ -0,0 +1,7 @@
+:export {
+  blackShadow: _single_import_export_source__localName;
+}
+
+._single_import_export_colors__blackShadow {
+  box-shadow: 0 0 10px -2px black;
+}

test/cssi/interchange-format/expected.css

@@ -0,0 +1,8 @@
+
+._single_import_export_colors__blackShadow {
+  box-shadow: 0 0 10px -2px black;
+}
+
+._single_import_export_source__localName {
+  color: red;
+}

test/cssi/interchange-format/expected.json

@@ -0,0 +1,3 @@
+{
+  "localName": "_single_import_export_source__localName _single_import_export_colors__blackShadow"
+}

test/cssi/interchange-format/source.css

@@ -0,0 +1,11 @@
+:imports("./colors.css") {
+  __tmp_import_djhgdsag: blackShadow;
+}
+
+:exports {
+  localName: _single_import_export_source__localName __tmp_import_djhgdsag;
+}
+
+._single_import_export_source__localName {
+  color: red;
+}