test: add validation test for liveReload option (#3718)

Author: snitin315

test/__snapshots__/validate-options.test.js.snap.webpack4

@@ -432,6 +432,13 @@ exports[`options validate should throw an error on the "ipc" option with 'false'
     * options.ipc should be true."
 `;
 
+exports[`options validate should throw an error on the "liveReload" option with 'invalid' value 1`] = `
+"ValidationError: Invalid options object. Dev Server has been initialized using an options object that does not match the API schema.
+ - options.liveReload should be a boolean.
+   -> Enables reload/refresh the page(s) when file changes are detected (enabled by default).
+   -> Read more at https://webpack.js.org/configuration/dev-server/#devserverlivereload"
+`;
+
 exports[`options validate should throw an error on the "onAfterSetupMiddleware" option with 'false' value 1`] = `
 "ValidationError: Invalid options object. Dev Server has been initialized using an options object that does not match the API schema.
  - options.onAfterSetupMiddleware should be an instance of function.

test/__snapshots__/validate-options.test.js.snap.webpack5

@@ -432,6 +432,13 @@ exports[`options validate should throw an error on the "ipc" option with 'false'
     * options.ipc should be true."
 `;
 
+exports[`options validate should throw an error on the "liveReload" option with 'invalid' value 1`] = `
+"ValidationError: Invalid options object. Dev Server has been initialized using an options object that does not match the API schema.
+ - options.liveReload should be a boolean.
+   -> Enables reload/refresh the page(s) when file changes are detected (enabled by default).
+   -> Read more at https://webpack.js.org/configuration/dev-server/#devserverlivereload"
+`;
+
 exports[`options validate should throw an error on the "onAfterSetupMiddleware" option with 'false' value 1`] = `
 "ValidationError: Invalid options object. Dev Server has been initialized using an options object that does not match the API schema.
  - options.onAfterSetupMiddleware should be an instance of function.

test/validate-options.test.js

@@ -237,6 +237,10 @@ const tests = {
     success: [true, path.resolve(os.tmpdir(), "webpack-dev-server.socket")],
     failure: [false, {}],
   },
+  liveReload: {
+    success: [true, false],
+    failure: ["invalid"],
+  },
   onListening: {
     success: [() => {}],
     failure: [""],