cypress: add a custom ESLint rule against cy.get().contains() usage.

Since cypress retries only the last command, it's better to use
the compact cy.contains(selector, content) version, instead of
cy.get(selector).contains(content) call.

Change-Id: Ie1f4c17bbf736058ecf6bd996b46384fdff19446
Reviewed-on: https://gerrit.libreoffice.org/c/online/+/93081
Tested-by: Jenkins CollaboraOffice <jenkinscollaboraoffice@gmail.com>
Reviewed-by: Tamás Zolnai <tamas.zolnai@collabora.com>

cypress_test/.eslintrc

@@ -1,5 +1,9 @@
 {
   "extends": "../loleaflet/.eslintrc",
+  "plugins": ["cypress-rules"],
+  "rules": {
+      "cypress-rules/no-get-contains-chain": 2
+  },
   "parserOptions": {
       "ecmaVersion": 6,
       "sourceType": "module",

cypress_test/eslint_plugin/index.js

@@ -0,0 +1,31 @@
+module.exports = {
+	rules: {
+		'no-get-contains-chain': {
+			/**
+			* Catches cy.get(selector).contains(content) calls in the code.
+			*
+			* Issue: In cypress test framework only the last command is retried.
+			* In this case it's the contains method and so the get() method is
+			* not retried. Sometimes, it behaves unexpectedly, because the DOM
+			* has the correct item matching with both the selector and the content,
+			* but the test still fails on this command chain.
+			*
+			* Fix 1: When we use the content as a selector. In this case, we can use
+			* cy.contains(selector, content) instead. This is compact command which
+			* will retry to match both the selector and the content.
+			*
+			* Fix 2: When we need an assertion about the content. In this case, we can
+			* use cy.contains(selector, content) or cy.get(selector).should('have.text', content)
+			* is also a good replacement.
+			*
+			**/
+			create: function(context) {
+				return {
+					'CallExpression[callee.property.name=\'contains\'][callee.object.callee.property.name=\'get\']': function(node) {
+						context.report(node, 'Do not chain get() and contains(). Use cy.contains(selector, content) instead for better retriability!');
+					}
+				};
+			}
+		}
+	}
+};

cypress_test/eslint_plugin/package.json

@@ -0,0 +1,5 @@
+{
+  "name": "eslint-plugin-cypress-rules",
+  "version": "1.0.0",
+  "main": "index.js"
+}

cypress_test/integration_tests/mobile/calc/insertion_wizard_spec.js

@@ -64,7 +64,7 @@ describe('Calc insertion wizard.', function() {
 		calcHelper.selectAllMobile();
 
 		cy.get('#copy-paste-container table td a')
-			.contains('some text');
+			.should('have.text', 'some text');
 
 		cy.get('#copy-paste-container table td a')
 			.should('have.attr', 'href', 'http://www.something.com');

cypress_test/package.json

@@ -7,6 +7,7 @@
     "cypress": "4.3.0",
     "cypress-failed-log": "2.6.2",
     "eslint": "6.8.0",
+    "eslint-plugin-cypress-rules": "file:eslint_plugin",
     "get-port-cli": "2.0.0",
     "wait-on": "4.0.0"
   },