test: add jest snapshot test for icss-compatible output

Author: k-g-a

__tests__/__data__/test.pcss

@@ -0,0 +1,15 @@
+.parent {
+  color: red;
+
+  & .child {
+    color: green;
+  }
+}
+
+.list {
+  color: red;
+
+  &_item {
+    color: green;
+  }
+}

__tests__/__snapshots__/index.test.js.snap

@@ -0,0 +1,27 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`Generates proper output for icss-utils: test-icss-compatible-output 1`] = `
+".test_parent_HASH {
+  color: red
+}
+
+  .test_parent_HASH .test_child_HASH {
+    color: green;
+  }
+
+.test_list_HASH {
+  color: red
+}
+
+.test_list_item_HASH {
+    color: green;
+  }
+
+:export {
+  parent: test_parent_HASH;
+  child: test_child_HASH;
+  list: test_list_HASH;
+  list_item: test_list_item_HASH
+}
+"
+`;

__tests__/index.test.js

@@ -0,0 +1,27 @@
+const fs = require("fs");
+const path = require("path");
+const { test, expect } = require("@jest/globals");
+const postcss = require("postcss");
+const nestedOnce = require("../index");
+const localByDefault = require("postcss-modules-local-by-default");
+const modulesScope = require("postcss-modules-scope");
+
+test("Generates proper output for icss-utils", async () => {
+  const from = path.join(__dirname, "__data__", "test.pcss");
+  const contents = fs.readFileSync(from);
+
+  const postcssInstance = postcss([
+    nestedOnce({ preserveEmpty: true }),
+    localByDefault({ mode: "local" }),
+    modulesScope({
+      generateScopedName: (local, file) => {
+        const name = path.basename(file, ".pcss");
+        return `${name}_${local}_HASH`;
+      },
+    }),
+  ]);
+
+  const result = await postcssInstance.process(contents, { from: from });
+
+  expect(result.css).toMatchSnapshot("test-icss-compatible-output");
+});

__tests__/test-postcss.cjs

@@ -0,0 +1,34 @@
+const fs = require('fs');
+const path = require('path');
+const potcss = require('postcss');
+const nestedOnce = require('../index');
+const modulesValues = require('postcss-modules-values');
+const localByDefault = require('postcss-modules-local-by-default');
+const extractImports = require('postcss-modules-extract-imports');
+const modulesScope = require('postcss-modules-scope');
+
+
+const FROM = path.join(__dirname, 'test.pcss');
+const TO = path.join(__dirname, 'test-postcss.css');
+const contents = fs.readFileSync(FROM);
+
+
+potcss([
+  nestedOnce({ preserveEmpty: true }),
+  modulesValues({}),
+  localByDefault({ mode: 'local' }),
+  extractImports(),
+  modulesScope({
+    generateScopedName: (local, file, css) => {
+      const { dir, name, base } = path.parse(file);
+      return `${name}_${local}_HASH`;
+    },
+  }),
+])
+  .process(contents, { from: FROM, to: TO })
+  .then((result) => {
+    fs.writeFileSync(TO, result.css);
+    if (result.map) {
+      fs.writeFileSync(`${TO}.map`, result.map.toString());
+    }
+  });

package.json

@@ -6,6 +6,7 @@
     "postcss",
     "css",
     "postcss-plugin",
+    "postcss-nested",
     "sass",
     "nested"
   ],
@@ -25,7 +26,11 @@
     "postcss": "^8.3.5"
   },
   "devDependencies": {
+    "@types/jest": "^26.0.23",
+    "jest": "^27.0.6",
     "postcss": "^8.3.5",
+    "postcss-modules-local-by-default": "^4.0.0",
+    "postcss-modules-scope": "^3.0.0",
     "prettier": "^2.3.2"
   }
 }