feat(tests): add Jest configuration and comprehensive tests for utility functions in index.js to ensure functionality and reliability

chore(package): update @actions/github dependency to version 6.0.1 and add Jest as a dev dependency with a test script

index.js

@@ -99,7 +99,7 @@ const formatDescription = (description) => {
     let edit = removeCarriageReturn(description);
     edit = removeHTMLComments(edit);
     edit = reduceNewlines(edit);
-        
+
     if (core.getBooleanInput('remove_github_reference_links')) {
         edit = removeGithubReferenceLinks(edit);
     }
@@ -276,3 +276,16 @@ const run = async () => {
 run()
     .then(() => core.info('Action completed successfully'))
     .catch(err => core.setFailed(err.message));
+
+// Export utility functions for testing
+export {
+    removeCarriageReturn,
+    removeHTMLComments,
+    reduceNewlines,
+    convertMentionsToLinks,
+    removeGithubReferenceLinks,
+    reduceHeadings,
+    convertLinksToMarkdown,
+    limitString,
+    formatDescription
+};

jest.config.mjs

@@ -0,0 +1,4 @@
+export default {
+  testEnvironment: 'node',
+  transform: {},
+};

package.json

@@ -23,7 +23,13 @@
   "license": "MIT",
   "dependencies": {
     "@actions/core": "^1.10.1",
-    "@actions/github": "^5.1.1",
+    "@actions/github": "^6.0.1",
     "node-fetch": "^3.3.2"
+  },
+  "devDependencies": {
+    "jest": "^30.0.0"
+  },
+  "scripts": {
+    "test": "node --experimental-vm-modules node_modules/.bin/jest"
   }
 }

tests/index.test.js

@@ -0,0 +1,222 @@
+import {
+    removeCarriageReturn,
+    removeHTMLComments,
+    reduceNewlines,
+    convertMentionsToLinks,
+    removeGithubReferenceLinks,
+    reduceHeadings,
+    convertLinksToMarkdown,
+    limitString,
+    formatDescription
+} from '../index.js';
+import { jest } from '@jest/globals';
+
+// ESM-compatible mock for @actions/core
+import * as core from '@actions/core';
+jest.unstable_mockModule('@actions/core', () => ({
+    getBooleanInput: (name) => false,
+    getInput: (name) => '',
+    setFailed: jest.fn(),
+    info: jest.fn(),
+    warning: jest.fn()
+}));
+
+describe('index.js utility functions', () => {
+    test('removeCarriageReturn removes \r', () => {
+        expect(removeCarriageReturn('foo\rbar\r\n')).toBe('foobar\n');
+    });
+
+    test('removeHTMLComments removes HTML comments', () => {
+        expect(removeHTMLComments('foo<!-- comment -->bar')).toBe('foobar');
+        expect(removeHTMLComments('foo<!-- multi\nline -->bar')).toBe('foobar');
+    });
+
+    test('reduceNewlines reduces multiple newlines', () => {
+        expect(reduceNewlines('a\n\n\n\nb')).toBe('a\n\nb');
+        expect(reduceNewlines('a\n\nb')).toBe('a\n\nb');
+    });
+
+    test('convertMentionsToLinks converts @user to markdown link', () => {
+        expect(convertMentionsToLinks('Hello @octocat!')).toBe('Hello [@octocat](https://github.com/octocat)!');
+        expect(convertMentionsToLinks('No mention here')).toBe('No mention here');
+    });
+
+    test('removeGithubReferenceLinks removes PR/commit/issue links', () => {
+        const input = '[PR](https://github.com/owner/repo/pull/1) [Commit](https://github.com/owner/repo/commit/abc123) [Issue](https://github.com/owner/repo/issues/2)';
+        expect(removeGithubReferenceLinks(input)).toBe('  ');
+    });
+
+    test('removeGithubReferenceLinks trims extra whitespace', () => {
+        const input = '[PR](https://github.com/owner/repo/pull/1) foo [Commit](https://github.com/owner/repo/commit/abc123) bar [Issue](https://github.com/owner/repo/issues/2)';
+        expect(removeGithubReferenceLinks(input)).toBe(' foo  bar ');
+    });
+
+    test('removeGithubReferenceLinks with no links returns original', () => {
+        const input = 'No links here!';
+        expect(removeGithubReferenceLinks(input)).toBe('No links here!');
+    });
+
+    test('convertMentionsToLinks does not convert invalid usernames', () => {
+        expect(convertMentionsToLinks('Hello @-invalid!')).toBe('Hello @-invalid!');
+        expect(convertMentionsToLinks('Hello @user--name!')).toBe('Hello @user--name!');
+    });
+
+    test('reduceNewlines keeps max 2 newlines', () => {
+        expect(reduceNewlines('a\n\n\n\n\n\nb')).toBe('a\n\nb');
+    });
+
+    test('reduceHeadings reduces headings', () => {
+        expect(reduceHeadings('### Heading3')).toBe('**__Heading3__**');
+        expect(reduceHeadings('## Heading2')).toBe('**Heading2**');
+    });
+
+    test('convertLinksToMarkdown converts PR/issue/changelog links', () => {
+        const pr = 'https://github.com/owner/repo/pull/1';
+        const issue = 'https://github.com/owner/repo/issues/2';
+        const changelog = 'https://github.com/owner/repo/compare/v1.0.0...v1.1.0';
+        expect(convertLinksToMarkdown(pr)).toBe('[PR #1](https://github.com/owner/repo/pull/1)');
+        expect(convertLinksToMarkdown(issue)).toBe('[Issue #2](https://github.com/owner/repo/issues/2)');
+        expect(convertLinksToMarkdown(changelog)).toBe('[v1.0.0...v1.1.0](https://github.com/owner/repo/compare/v1.0.0...v1.1.0)');
+    });
+
+    test('convertLinksToMarkdown ignores existing markdown links', () => {
+        const input = '[already](https://github.com/owner/repo/pull/1) and https://github.com/owner/repo/pull/2';
+        expect(convertLinksToMarkdown(input)).toBe('[already](https://github.com/owner/repo/pull/1) and [PR #2](https://github.com/owner/repo/pull/2)');
+    });
+
+    describe('limitString', () => {
+        test('returns string unchanged if under maxLength', () => {
+            expect(limitString('short', 10)).toBe('short');
+        });
+        test('truncates and adds ellipsis if over maxLength', () => {
+            expect(limitString('1234567890', 5)).toBe('…');
+        });
+        test('truncates and adds markdown link if url provided', () => {
+            expect(limitString('abcdef', 5, 'http://x')).toBe('([…](http://x))');
+        });
+        test('clips at newline if clipAtLine is true', () => {
+            expect(limitString('abc\ndef', 5, undefined, true)).toMatch(/\n…$/);
+        });
+
+        // Edge cases for empty, null, and undefined input
+        test('removeCarriageReturn handles empty, null, undefined', () => {
+            expect(removeCarriageReturn('')).toBe('');
+            expect(() => removeCarriageReturn(null)).toThrow();
+            expect(() => removeCarriageReturn(undefined)).toThrow();
+        });
+
+        test('removeHTMLComments handles empty, null, undefined', () => {
+            expect(removeHTMLComments('')).toBe('');
+            expect(() => removeHTMLComments(null)).toThrow();
+            expect(() => removeHTMLComments(undefined)).toThrow();
+        });
+
+        test('reduceNewlines handles empty, null, undefined', () => {
+            expect(reduceNewlines('')).toBe('');
+            expect(() => reduceNewlines(null)).toThrow();
+            expect(() => reduceNewlines(undefined)).toThrow();
+        });
+
+        test('convertMentionsToLinks handles empty, null, undefined', () => {
+            expect(convertMentionsToLinks('')).toBe('');
+            expect(() => convertMentionsToLinks(null)).toThrow();
+            expect(() => convertMentionsToLinks(undefined)).toThrow();
+        });
+
+        test('removeGithubReferenceLinks handles empty, null, undefined', () => {
+            expect(removeGithubReferenceLinks('')).toBe('');
+            expect(() => removeGithubReferenceLinks(null)).toThrow();
+            expect(() => removeGithubReferenceLinks(undefined)).toThrow();
+        });
+
+        test('reduceHeadings handles empty, null, undefined', () => {
+            expect(reduceHeadings('')).toBe('');
+            expect(() => reduceHeadings(null)).toThrow();
+            expect(() => reduceHeadings(undefined)).toThrow();
+        });
+
+        test('convertLinksToMarkdown handles empty, null, undefined', () => {
+            expect(convertLinksToMarkdown('')).toBe('');
+            expect(() => convertLinksToMarkdown(null)).toThrow();
+            expect(() => convertLinksToMarkdown(undefined)).toThrow();
+        });
+
+        // limitString edge cases
+        describe('limitString edge cases', () => {
+            test('returns empty string if input is empty', () => {
+                expect(limitString('', 5)).toBe('');
+            });
+            test('returns ellipsis if maxLength is 0', () => {
+                expect(limitString('abc', 0)).toBe('…');
+            });
+            test('returns string unchanged if string is exactly maxLength', () => {
+                expect(limitString('abc', 3)).toBe('abc');
+            });
+            test('handles empty url', () => {
+                expect(limitString('abcdef', 5, '')).toBe('…');
+            });
+        });
+
+        // convertMentionsToLinks edge case: multiple mentions
+        test('convertMentionsToLinks handles multiple mentions', () => {
+            expect(convertMentionsToLinks('Hi @foo and @bar!')).toBe('Hi [@foo](https://github.com/foo) and [@bar](https://github.com/bar)!');
+        });
+
+        // convertLinksToMarkdown edge case: multiple links
+        test('convertLinksToMarkdown handles multiple links', () => {
+            const input = 'https://github.com/owner/repo/pull/1 and https://github.com/owner/repo/issues/2';
+            expect(convertLinksToMarkdown(input)).toBe('[PR #1](https://github.com/owner/repo/pull/1) and [Issue #2](https://github.com/owner/repo/issues/2)');
+        });
+
+        // reduceHeadings edge case: mixed headings and text
+        test('reduceHeadings handles mixed headings and text', () => {
+            const input = '## H2\n### H3\nNormal text';
+            expect(reduceHeadings(input)).toBe('**H2**\n**__H3__**\nNormal text');
+        });
+
+        // Whitespace-only input
+        test('removeCarriageReturn handles whitespace-only', () => {
+            expect(removeCarriageReturn('   \r\r\r   ')).toBe('      ');
+        });
+        test('reduceNewlines handles whitespace-only', () => {
+            expect(reduceNewlines('   \n\n   ')).toBe('   \n   ');
+        });
+        test('removeHTMLComments handles whitespace-only', () => {
+            expect(removeHTMLComments('   ')).toBe('   ');
+        });
+
+        // Special characters and unicode
+        test('convertMentionsToLinks handles unicode usernames', () => {
+            expect(convertMentionsToLinks('Hi @üser!')).toBe('Hi [@üser](https://github.com/üser)!');
+        });
+        test('convertLinksToMarkdown handles unicode in links', () => {
+            const input = 'https://github.com/owner/repo/pull/ü123';
+            expect(convertLinksToMarkdown(input)).toBe('https://github.com/owner/repo/pull/ü123'); // not matched as PR
+        });
+
+        // Long string for limitString
+        test('limitString truncates very long string', () => {
+            const longStr = 'a'.repeat(1000);
+            expect(limitString(longStr, 10)).toBe('aaaaaaaaa…');
+        });
+
+        // No-op for reduceHeadings
+        test('reduceHeadings with no headings', () => {
+            expect(reduceHeadings('Just some text')).toBe('Just some text');
+        });
+
+        // Multiple consecutive mentions/links
+        test('convertMentionsToLinks handles consecutive mentions', () => {
+            expect(convertMentionsToLinks('@foo@bar')).toBe('[@foo](https://github.com/foo)[@bar](https://github.com/bar)');
+        });
+        test('convertLinksToMarkdown handles consecutive links', () => {
+            const input = 'https://github.com/owner/repo/pull/1https://github.com/owner/repo/issues/2';
+            expect(convertLinksToMarkdown(input)).toBe('[PR #1](https://github.com/owner/repo/pull/1)[Issue #2](https://github.com/owner/repo/issues/2)');
+        });
+
+        // Mixed valid and invalid mentions
+        test('convertMentionsToLinks handles mixed valid/invalid mentions', () => {
+            expect(convertMentionsToLinks('Hi @foo and @-bad!')).toBe('Hi [@foo](https://github.com/foo) and @-bad!');
+        });
+    });
+});