fix: [M3-9073] - Fix duplicate specs in Cypress Slack / GH notificati…

…ons (linode#11489)

* Avoid duplicating specs in run command output, reduce Slack failure list to 4

* Add changeset

packages/manager/.changeset/pr-11489-tests-1736348080190.md

@@ -0,0 +1,5 @@
+---
+"@linode/manager": Tests
+---
+
+Fix test notification formatting and output issues ([#11489](https://github.com/linode/manager/pull/11489))

scripts/junit-summary/formatters/slack-formatter.ts

@@ -14,7 +14,7 @@ import { cypressRunCommand } from '../util/cypress';
  * The Slack notification has a maximum character limit, so we must truncate
  * the failure results to reduce the risk of hitting that limit.
  */
-const FAILURE_SUMMARY_LIMIT = 6;
+const FAILURE_SUMMARY_LIMIT = 4;
 
 /**
  * Outputs test result summary formatted as a Slack message.

scripts/junit-summary/util/cypress.ts

@@ -6,6 +6,7 @@
  * @returns Cypress run command to run `testFiles`.
  */
 export const cypressRunCommand = (testFiles: string[]): string => {
-  const testFilesList = testFiles.join(',');
+  const dedupedTestFiles = Array.from(new Set(testFiles));
+  const testFilesList = dedupedTestFiles.join(',');
   return `yarn cy:run -s "${testFilesList}"`;
 };