diff --git a/services/web/test/unit/src/BetaProgram/BetaProgramController.test.mjs b/services/web/test/unit/src/BetaProgram/BetaProgramController.test.mjs
index 586aaf195d..b1fc8cf2fa 100644
--- a/services/web/test/unit/src/BetaProgram/BetaProgramController.test.mjs
+++ b/services/web/test/unit/src/BetaProgram/BetaProgramController.test.mjs
@@ -80,12 +80,16 @@ describe('BetaProgramController', function () {
 
   describe('optIn', function () {
     it("should redirect to '/beta/participate'", async function (ctx) {
-      await new Promise(resolve => {
+      await new Promise((resolve, reject) => {
         ctx.res.callback = () => {
           ctx.res.redirectedTo.should.equal('/beta/participate')
           resolve()
         }
-        ctx.BetaProgramController.optIn(ctx.req, ctx.res)
+        ctx.BetaProgramController.optIn(
+          ctx.req,
+          ctx.res,
+          ctx.rejectOnError(reject)
+        )
       })
     })
 
@@ -134,37 +138,49 @@ describe('BetaProgramController', function () {
 
   describe('optOut', function () {
     it("should redirect to '/beta/participate'", async function (ctx) {
-      await new Promise(resolve => {
+      await new Promise((resolve, reject) => {
         ctx.res.callback = () => {
           expect(ctx.res.redirectedTo).to.equal('/beta/participate')
           resolve()
         }
-        ctx.BetaProgramController.optOut(ctx.req, ctx.res)
+        ctx.BetaProgramController.optOut(
+          ctx.req,
+          ctx.res,
+          ctx.rejectOnError(reject)
+        )
       })
     })
 
     it('should not call next with an error', async function (ctx) {
-      await new Promise(resolve => {
+      await new Promise((resolve, reject) => {
         ctx.res.callback = () => {
           ctx.next.callCount.should.equal(0)
           resolve()
         }
-        ctx.BetaProgramController.optOut(ctx.req, ctx.res)
+        ctx.BetaProgramController.optOut(
+          ctx.req,
+          ctx.res,
+          ctx.rejectOnError(reject)
+        )
       })
     })
 
     it('should call BetaProgramHandler.optOut', async function (ctx) {
-      await new Promise(resolve => {
+      await new Promise((resolve, reject) => {
         ctx.res.callback = () => {
           ctx.BetaProgramHandler.promises.optOut.callCount.should.equal(1)
           resolve()
         }
-        ctx.BetaProgramController.optOut(ctx.req, ctx.res)
+        ctx.BetaProgramController.optOut(
+          ctx.req,
+          ctx.res,
+          ctx.rejectOnError(reject)
+        )
       })
     })
 
     it('should invoke the session maintenance', async function (ctx) {
-      await new Promise(resolve => {
+      await new Promise((resolve, reject) => {
         ctx.res.callback = () => {
           ctx.SplitTestSessionHandler.promises.sessionMaintenance.should.have.been.calledWith(
             ctx.req,
@@ -172,7 +188,11 @@ describe('BetaProgramController', function () {
           )
           resolve()
         }
-        ctx.BetaProgramController.optOut(ctx.req, ctx.res)
+        ctx.BetaProgramController.optOut(
+          ctx.req,
+          ctx.res,
+          ctx.rejectOnError(reject)
+        )
       })
     })
 
@@ -208,12 +228,16 @@ describe('BetaProgramController', function () {
     })
 
     it('should render the opt-in page', async function (ctx) {
-      await new Promise(resolve => {
+      await new Promise((resolve, reject) => {
         ctx.res.callback = () => {
           expect(ctx.res.renderedTemplate).to.equal('beta_program/opt_in')
           resolve()
         }
-        ctx.BetaProgramController.optInPage(ctx.req, ctx.res)
+        ctx.BetaProgramController.optInPage(
+          ctx.req,
+          ctx.res,
+          ctx.rejectOnError(reject)
+        )
       })
     })
 
diff --git a/services/web/test/unit/src/Contact/ContactController.test.mjs b/services/web/test/unit/src/Contact/ContactController.test.mjs
index fa23677a5b..06dd5b768a 100644
--- a/services/web/test/unit/src/Contact/ContactController.test.mjs
+++ b/services/web/test/unit/src/Contact/ContactController.test.mjs
@@ -89,7 +89,7 @@ describe('ContactController', function () {
     })
 
     it('should populate the users contacts ids', async function (ctx) {
-      await new Promise(resolve => {
+      await new Promise((resolve, reject) => {
         ctx.res.callback = () => {
           expect(ctx.UserGetter.promises.getUsers).to.have.been.calledWith(
             ctx.contact_ids,
@@ -102,12 +102,16 @@ describe('ContactController', function () {
           )
           resolve()
         }
-        ctx.ContactController.getContacts(ctx.req, ctx.res)
+        ctx.ContactController.getContacts(
+          ctx.req,
+          ctx.res,
+          ctx.rejectOnError(reject)
+        )
       })
     })
 
     it('should fire the getContact module hook', async function (ctx) {
-      await new Promise(resolve => {
+      await new Promise((resolve, reject) => {
         ctx.res.callback = () => {
           expect(ctx.Modules.promises.hooks.fire).to.have.been.calledWith(
             'getContacts',
@@ -115,12 +119,16 @@ describe('ContactController', function () {
           )
           resolve()
         }
-        ctx.ContactController.getContacts(ctx.req, ctx.res)
+        ctx.ContactController.getContacts(
+          ctx.req,
+          ctx.res,
+          ctx.rejectOnError(reject)
+        )
       })
     })
 
     it('should return a formatted list of contacts in contact list order, without holding accounts', async function (ctx) {
-      await new Promise(resolve => {
+      await new Promise((resolve, reject) => {
         ctx.res.callback = () => {
           ctx.res.json.args[0][0].contacts.should.deep.equal([
             {
@@ -140,7 +148,11 @@ describe('ContactController', function () {
           ])
           resolve()
         }
-        ctx.ContactController.getContacts(ctx.req, ctx.res)
+        ctx.ContactController.getContacts(
+          ctx.req,
+          ctx.res,
+          ctx.rejectOnError(reject)
+        )
       })
     })
   })
diff --git a/services/web/test/unit/src/User/UserPagesController.test.mjs b/services/web/test/unit/src/User/UserPagesController.test.mjs
index 8afc49c40f..f6252faa94 100644
--- a/services/web/test/unit/src/User/UserPagesController.test.mjs
+++ b/services/web/test/unit/src/User/UserPagesController.test.mjs
@@ -161,22 +161,25 @@ describe('UserPagesController', function () {
 
   describe('registerPage', function () {
     it('should render the register page', async function (ctx) {
-      await new Promise(resolve => {
+      await new Promise((resolve, reject) => {
         ctx.res.callback = () => {
           ctx.res.renderedTemplate.should.equal('user/register')
           resolve()
         }
-        ctx.UserPagesController.registerPage(ctx.req, ctx.res)
+        ctx.UserPagesController.registerPage(
+          ctx.req,
+          ctx.res,
+          ctx.rejectOnError(reject)
+        )
       })
     })
 
     it('should set sharedProjectData', async function (ctx) {
-      await new Promise(resolve => {
-        ctx.req.session.sharedProjectData = {
-          project_name: 'myProject',
-          user_first_name: 'user_first_name_here',
-        }
-
+      ctx.req.session.sharedProjectData = {
+        project_name: 'myProject',
+        user_first_name: 'user_first_name_here',
+      }
+      await new Promise((resolve, reject) => {
         ctx.res.callback = () => {
           ctx.res.renderedVariables.sharedProjectData.project_name.should.equal(
             'myProject'
@@ -186,12 +189,16 @@ describe('UserPagesController', function () {
           )
           resolve()
         }
-        ctx.UserPagesController.registerPage(ctx.req, ctx.res)
+        ctx.UserPagesController.registerPage(
+          ctx.req,
+          ctx.res,
+          ctx.rejectOnError(reject)
+        )
       })
     })
 
     it('should set newTemplateData', async function (ctx) {
-      await new Promise(resolve => {
+      await new Promise((resolve, reject) => {
         ctx.req.session.templateData = { templateName: 'templateName' }
 
         ctx.res.callback = () => {
@@ -200,12 +207,16 @@ describe('UserPagesController', function () {
           )
           resolve()
         }
-        ctx.UserPagesController.registerPage(ctx.req, ctx.res)
+        ctx.UserPagesController.registerPage(
+          ctx.req,
+          ctx.res,
+          ctx.rejectOnError(reject)
+        )
       })
     })
 
     it('should not set the newTemplateData if there is nothing in the session', async function (ctx) {
-      await new Promise(resolve => {
+      await new Promise((resolve, reject) => {
         ctx.res.callback = () => {
           assert.equal(
             ctx.res.renderedVariables.newTemplateData.templateName,
@@ -213,19 +224,27 @@ describe('UserPagesController', function () {
           )
           resolve()
         }
-        ctx.UserPagesController.registerPage(ctx.req, ctx.res)
+        ctx.UserPagesController.registerPage(
+          ctx.req,
+          ctx.res,
+          ctx.rejectOnError(reject)
+        )
       })
     })
   })
 
   describe('loginForm', function () {
     it('should render the login page', async function (ctx) {
-      await new Promise(resolve => {
+      await new Promise((resolve, reject) => {
         ctx.res.callback = () => {
           ctx.res.renderedTemplate.should.equal('user/login')
           resolve()
         }
-        ctx.UserPagesController.loginPage(ctx.req, ctx.res)
+        ctx.UserPagesController.loginPage(
+          ctx.req,
+          ctx.res,
+          ctx.rejectOnError(reject)
+        )
       })
     })
 
@@ -239,7 +258,7 @@ describe('UserPagesController', function () {
       })
 
       it('should set a redirect', async function (ctx) {
-        await new Promise(resolve => {
+        await new Promise((resolve, reject) => {
           ctx.res.callback = page => {
             ctx.AuthenticationController.setRedirectInSession.callCount.should.equal(
               1
@@ -249,7 +268,11 @@ describe('UserPagesController', function () {
             ).to.equal(ctx.req.query.redir)
             resolve()
           }
-          ctx.UserPagesController.loginPage(ctx.req, ctx.res)
+          ctx.UserPagesController.loginPage(
+            ctx.req,
+            ctx.res,
+            ctx.rejectOnError(reject)
+          )
         })
       })
     })
@@ -261,17 +284,21 @@ describe('UserPagesController', function () {
     })
 
     it('should render user/sessions', async function (ctx) {
-      await new Promise(resolve => {
+      await new Promise((resolve, reject) => {
         ctx.res.callback = () => {
           ctx.res.renderedTemplate.should.equal('user/sessions')
           resolve()
         }
-        ctx.UserPagesController.sessionsPage(ctx.req, ctx.res)
+        ctx.UserPagesController.sessionsPage(
+          ctx.req,
+          ctx.res,
+          ctx.rejectOnError(reject)
+        )
       })
     })
 
     it('should include current session data in the view', async function (ctx) {
-      await new Promise(resolve => {
+      await new Promise((resolve, reject) => {
         ctx.res.callback = () => {
           expect(ctx.res.renderedVariables.currentSession).to.deep.equal({
             ip_address: '1.1.1.1',
@@ -279,17 +306,25 @@ describe('UserPagesController', function () {
           })
           resolve()
         }
-        ctx.UserPagesController.sessionsPage(ctx.req, ctx.res)
+        ctx.UserPagesController.sessionsPage(
+          ctx.req,
+          ctx.res,
+          ctx.rejectOnError(reject)
+        )
       })
     })
 
     it('should have called getAllUserSessions', async function (ctx) {
-      await new Promise(resolve => {
+      await new Promise((resolve, reject) => {
         ctx.res.callback = page => {
           ctx.UserSessionsManager.getAllUserSessions.callCount.should.equal(1)
           resolve()
         }
-        ctx.UserPagesController.sessionsPage(ctx.req, ctx.res)
+        ctx.UserPagesController.sessionsPage(
+          ctx.req,
+          ctx.res,
+          ctx.rejectOnError(reject)
+        )
       })
     })
 
@@ -320,28 +355,36 @@ describe('UserPagesController', function () {
     })
 
     it('render page with subscribed status', async function (ctx) {
-      await new Promise(resolve => {
-        ctx.NewsletterManager.subscribed.yields(null, true)
+      ctx.NewsletterManager.subscribed.yields(null, true)
+      await new Promise((resolve, reject) => {
         ctx.res.callback = () => {
           ctx.res.renderedTemplate.should.equal('user/email-preferences')
           ctx.res.renderedVariables.title.should.equal('newsletter_info_title')
           ctx.res.renderedVariables.subscribed.should.equal(true)
           resolve()
         }
-        ctx.UserPagesController.emailPreferencesPage(ctx.req, ctx.res)
+        ctx.UserPagesController.emailPreferencesPage(
+          ctx.req,
+          ctx.res,
+          ctx.rejectOnError(reject)
+        )
       })
     })
 
     it('render page with unsubscribed status', async function (ctx) {
-      await new Promise(resolve => {
-        ctx.NewsletterManager.subscribed.yields(null, false)
+      ctx.NewsletterManager.subscribed.yields(null, false)
+      await new Promise((resolve, reject) => {
         ctx.res.callback = () => {
           ctx.res.renderedTemplate.should.equal('user/email-preferences')
           ctx.res.renderedVariables.title.should.equal('newsletter_info_title')
           ctx.res.renderedVariables.subscribed.should.equal(false)
           resolve()
         }
-        ctx.UserPagesController.emailPreferencesPage(ctx.req, ctx.res)
+        ctx.UserPagesController.emailPreferencesPage(
+          ctx.req,
+          ctx.res,
+          ctx.rejectOnError(reject)
+        )
       })
     })
   })
@@ -355,54 +398,70 @@ describe('UserPagesController', function () {
     })
 
     it('should render user/settings', async function (ctx) {
-      await new Promise(resolve => {
+      await new Promise((resolve, reject) => {
         ctx.res.callback = () => {
           ctx.res.renderedTemplate.should.equal('user/settings')
           resolve()
         }
-        ctx.UserPagesController.settingsPage(ctx.req, ctx.res)
+        ctx.UserPagesController.settingsPage(
+          ctx.req,
+          ctx.res,
+          ctx.rejectOnError(reject)
+        )
       })
     })
 
     it('should send user', async function (ctx) {
-      await new Promise(resolve => {
+      await new Promise((resolve, reject) => {
         ctx.res.callback = () => {
           ctx.res.renderedVariables.user.id.should.equal(ctx.user._id)
           ctx.res.renderedVariables.user.email.should.equal(ctx.user.email)
           resolve()
         }
-        ctx.UserPagesController.settingsPage(ctx.req, ctx.res)
+        ctx.UserPagesController.settingsPage(
+          ctx.req,
+          ctx.res,
+          ctx.rejectOnError(reject)
+        )
       })
     })
 
     it("should set 'shouldAllowEditingDetails' to true", async function (ctx) {
-      await new Promise(resolve => {
+      await new Promise((resolve, reject) => {
         ctx.res.callback = () => {
           ctx.res.renderedVariables.shouldAllowEditingDetails.should.equal(true)
           resolve()
         }
-        ctx.UserPagesController.settingsPage(ctx.req, ctx.res)
+        ctx.UserPagesController.settingsPage(
+          ctx.req,
+          ctx.res,
+          ctx.rejectOnError(reject)
+        )
       })
     })
 
     it('should restructure thirdPartyIdentifiers data for template use', async function (ctx) {
-      await new Promise(resolve => {
-        const expectedResult = {
-          google: 'testId',
-        }
+      const expectedResult = {
+        google: 'testId',
+      }
+      await new Promise((resolve, reject) => {
         ctx.res.callback = () => {
           expect(ctx.res.renderedVariables.thirdPartyIds).to.include(
             expectedResult
           )
           resolve()
         }
-        ctx.UserPagesController.settingsPage(ctx.req, ctx.res)
+        ctx.UserPagesController.settingsPage(
+          ctx.req,
+          ctx.res,
+          ctx.rejectOnError(reject)
+        )
       })
     })
 
     it("should set and clear 'projectSyncSuccessMessage'", async function (ctx) {
-      await new Promise(resolve => {
-        ctx.req.session.projectSyncSuccessMessage = 'Some Sync Success'
+      ctx.req.session.projectSyncSuccessMessage = 'Some Sync Success'
+      await new Promise((resolve, reject) => {
         ctx.res.callback = () => {
           ctx.res.renderedVariables.projectSyncSuccessMessage.should.equal(
             'Some Sync Success'
@@ -410,12 +469,16 @@ describe('UserPagesController', function () {
           expect(ctx.req.session.projectSyncSuccessMessage).to.not.exist
           resolve()
         }
-        ctx.UserPagesController.settingsPage(ctx.req, ctx.res)
+        ctx.UserPagesController.settingsPage(
+          ctx.req,
+          ctx.res,
+          ctx.rejectOnError(reject)
+        )
       })
     })
 
     it('should cast refProviders to booleans', async function (ctx) {
-      await new Promise(resolve => {
+      await new Promise((resolve, reject) => {
         ctx.res.callback = () => {
           expect(ctx.res.renderedVariables.user.refProviders).to.deep.equal({
             mendeley: true,
@@ -424,53 +487,60 @@ describe('UserPagesController', function () {
           })
           resolve()
         }
-        ctx.UserPagesController.settingsPage(ctx.req, ctx.res)
+        ctx.UserPagesController.settingsPage(
+          ctx.req,
+          ctx.res,
+          ctx.rejectOnError(reject)
+        )
       })
     })
 
     it('should send the correct managed user admin email', async function (ctx) {
-      await new Promise(resolve => {
+      await new Promise((resolve, reject) => {
         ctx.res.callback = () => {
           expect(
             ctx.res.renderedVariables.currentManagedUserAdminEmail
           ).to.equal(ctx.adminEmail)
           resolve()
         }
-        ctx.UserPagesController.settingsPage(ctx.req, ctx.res)
+        ctx.UserPagesController.settingsPage(
+          ctx.req,
+          ctx.res,
+          ctx.rejectOnError(reject)
+        )
       })
     })
 
     it('should send info for groups with SSO enabled', async function (ctx) {
-      await new Promise(resolve => {
-        ctx.user.enrollment = {
-          sso: [
-            {
-              groupId: 'abc123abc123',
-              primary: true,
-              linkedAt: new Date(),
-            },
-          ],
-        }
-        const group1 = {
-          _id: 'abc123abc123',
-          teamName: 'Group SSO Rulz',
-          admin_id: {
-            email: 'admin.email@ssolove.com',
+      ctx.user.enrollment = {
+        sso: [
+          {
+            groupId: 'abc123abc123',
+            primary: true,
+            linkedAt: new Date(),
           },
-          linked: true,
-        }
-        const group2 = {
-          _id: 'def456def456',
-          admin_id: {
-            email: 'someone.else@noname.co.uk',
-          },
-          linked: false,
-        }
-
-        ctx.Modules.promises.hooks.fire
-          .withArgs('getUserGroupsSSOEnrollmentStatus')
-          .resolves([[group1, group2]])
+        ],
+      }
+      const group1 = {
+        _id: 'abc123abc123',
+        teamName: 'Group SSO Rulz',
+        admin_id: {
+          email: 'admin.email@ssolove.com',
+        },
+        linked: true,
+      }
+      const group2 = {
+        _id: 'def456def456',
+        admin_id: {
+          email: 'someone.else@noname.co.uk',
+        },
+        linked: false,
+      }
 
+      ctx.Modules.promises.hooks.fire
+        .withArgs('getUserGroupsSSOEnrollmentStatus')
+        .resolves([[group1, group2]])
+      await new Promise((resolve, reject) => {
         ctx.res.callback = () => {
           expect(
             ctx.res.renderedVariables.memberOfSSOEnabledGroups
@@ -491,7 +561,11 @@ describe('UserPagesController', function () {
           resolve()
         }
 
-        ctx.UserPagesController.settingsPage(ctx.req, ctx.res)
+        ctx.UserPagesController.settingsPage(
+          ctx.req,
+          ctx.res,
+          ctx.rejectOnError(reject)
+        )
       })
     })
 
@@ -505,14 +579,18 @@ describe('UserPagesController', function () {
       })
 
       it('should set "shouldAllowEditingDetails" to false', async function (ctx) {
-        await new Promise(resolve => {
+        await new Promise((resolve, reject) => {
           ctx.res.callback = () => {
             ctx.res.renderedVariables.shouldAllowEditingDetails.should.equal(
               false
             )
             resolve()
           }
-          ctx.UserPagesController.settingsPage(ctx.req, ctx.res)
+          ctx.UserPagesController.settingsPage(
+            ctx.req,
+            ctx.res,
+            ctx.rejectOnError(reject)
+          )
         })
       })
     })
@@ -527,14 +605,18 @@ describe('UserPagesController', function () {
       })
 
       it('should set "shouldAllowEditingDetails" to false', async function (ctx) {
-        await new Promise(resolve => {
+        await new Promise((resolve, reject) => {
           ctx.res.callback = () => {
             ctx.res.renderedVariables.shouldAllowEditingDetails.should.equal(
               false
             )
             resolve()
           }
-          ctx.UserPagesController.settingsPage(ctx.req, ctx.res)
+          ctx.UserPagesController.settingsPage(
+            ctx.req,
+            ctx.res,
+            ctx.rejectOnError(reject)
+          )
         })
       })
     })
diff --git a/services/web/test/unit/vitest_bootstrap.mjs b/services/web/test/unit/vitest_bootstrap.mjs
index 5a39b2d587..e00720c5d6 100644
--- a/services/web/test/unit/vitest_bootstrap.mjs
+++ b/services/web/test/unit/vitest_bootstrap.mjs
@@ -36,6 +36,14 @@ vi.mock('@overleaf/logger', async () => {
 })
 
 beforeEach(ctx => {
+  // This function is a utility to duplicate the behaviour of passing `done` in place of `next` in an express route handler.
+  ctx.rejectOnError = reject => {
+    return err => {
+      if (err) {
+        reject(err)
+      }
+    }
+  }
   ctx.logger = logger
 })