🔧 Added custom rollup config for tests

packages/core/rollup.tests.js

@@ -0,0 +1,24 @@
+import babel from "rollup-plugin-babel";
+import resolve from "rollup-plugin-node-resolve";
+import commonjs from "rollup-plugin-commonjs";
+import json from "rollup-plugin-json";
+
+export default {
+  input: "src/index.js",
+  output: [
+    {
+      file: "tests/dist/index.js",
+      format: "cjs",
+      sourcemap: true
+    }
+  ],
+  plugins: [
+    resolve(),
+    json(),
+    commonjs(),
+    babel({
+      exclude: "node_modules/**",
+      plugins: ["@babel/plugin-proposal-object-rest-spread"]
+    })
+  ]
+};