Convert ActionCable tests from CoffeeScript to ES2015 and replace Blade with Karma and Rollup (#34440)

* Rename .coffee files in ActionCable test suite in prep for decaffeination

* Decaffeinate ActionCable tests

* Replace Blade with Karma and Rollup to run ActionCable JS tests

- Add karma and qunit devDependencies

- Add test script to ActionCable package

- Use rollup to bundle ActionCable tests

- Use karma as the ActionCable JS test runner

* Replace vendored mock-socket with package devDependency in ActionCable

* Move ActionCable yarn install to TravisCI before_install config

* Clean up decaffeinated ActionCable tests to use consistent formatting

1 files changed, 18 insertions, 0 deletions

diff --git a/actioncable/rollup.config.test.js b/actioncable/rollup.config.test.js
new file mode 100644
index 0000000000..f92ff36240
--- /dev/null
+++ b/actioncable/rollup.config.test.js
@@ -0,0 +1,18 @@
+import babel from "rollup-plugin-babel"
+import commonjs from "rollup-plugin-commonjs"
+import resolve from "rollup-plugin-node-resolve"
+
+export default {
+  input: "test/javascript/src/test.js",
+
+  output: {
+    file: "test/javascript/compiled/test.js",
+    format: "iife"
+  },
+
+  plugins: [
+    resolve(),
+    commonjs(),
+    babel()
+  ]
+}