Update tests for changelog updates

Author: NickColley

shared/github-scripts/changelog-release-helper.unit.test.mjs

@@ -1,4 +1,5 @@
 import fs from 'fs'
+import { join } from 'path'
 
 import { outdent } from 'outdent'
 
@@ -9,6 +10,13 @@ import {
 
 jest.mock('fs')
 
+const CHANGELOG_FILE_PATH = join(
+  import.meta.dirname,
+  '..',
+  '..',
+  'CHANGELOG.md'
+)
+
 describe('Changelog release helper', () => {
   beforeEach(() => {
     jest.mocked(fs.readFileSync).mockReturnValue(`
@@ -26,15 +34,15 @@ describe('Changelog release helper', () => {
     it('adds a new heading to the changelog for the new version', () => {
       updateChangelog('3.1.0', '3.0.0')
       expect(fs.writeFileSync).toHaveBeenCalledWith(
-        './CHANGELOG.md',
+        CHANGELOG_FILE_PATH,
         expect.stringContaining('## v3.1.0 (Feature release)')
       )
     })
 
     it('prefixes a new heading with a pre-release identifier if the new version is a pre-release', () => {
       updateChangelog('3.1.0-beta.0', '3.0.0')
       expect(fs.writeFileSync).toHaveBeenCalledWith(
-        './CHANGELOG.md',
+        CHANGELOG_FILE_PATH,
         expect.stringContaining('## v3.1.0-beta.0 (Beta feature release)')
       )
     })
@@ -52,7 +60,7 @@ describe('Changelog release helper', () => {
 
       updateChangelog('3.1.0-beta.1', '3.1.0-beta.0')
       expect(fs.writeFileSync).toHaveBeenCalledWith(
-        './CHANGELOG.md',
+        CHANGELOG_FILE_PATH,
         expect.stringContaining('## v3.1.0-beta.1 (Beta feature release)')
       )
     })
@@ -70,7 +78,7 @@ describe('Changelog release helper', () => {
 
       updateChangelog('3.1.0-beta.1', '3.1.0-beta.0')
       expect(fs.writeFileSync).toHaveBeenCalledWith(
-        './CHANGELOG.md',
+        CHANGELOG_FILE_PATH,
         expect.stringContaining(outdent`
           ## v3.1.0-beta.1 (Beta feature release)
           > [!WARNING]
@@ -79,7 +87,7 @@ describe('Changelog release helper', () => {
         `)
       )
       expect(fs.writeFileSync).toHaveBeenCalledWith(
-        './CHANGELOG.md',
+        CHANGELOG_FILE_PATH,
         expect.stringContaining('To install this version with npm')
       )
     })
@@ -97,7 +105,7 @@ describe('Changelog release helper', () => {
 
       updateChangelog('3.1.1', '3.1.0')
       expect(fs.writeFileSync).not.toHaveBeenCalledWith(
-        './CHANGELOG.md',
+        CHANGELOG_FILE_PATH,
         expect.stringContaining('> [!WARNING]')
       )
     })
@@ -115,7 +123,7 @@ describe('Changelog release helper', () => {
 
       updateChangelog('3.1.1', '3.1.0')
       expect(fs.writeFileSync).toHaveBeenCalledWith(
-        './CHANGELOG.md',
+        CHANGELOG_FILE_PATH,
         expect.stringContaining(outdent`
             ## v3.1.1 (Fix release)
             To install this version with npm, run \`npm install govuk-frontend@3.1.1\`. You can also find more information about [how to stay up to date](https://frontend.design-system.service.gov.uk/staying-up-to-date/#updating-to-the-latest-version) in our documentation.