AUT-3779: Extract template selection logic to function with tests

Introduces the getAccountNotFoundTemplate function which replicates
existing template selection logic previously included in the controller
and calls getChannelSpecificTemplate.

I've opted to do this because the additional requirement to select a
template that is appropriate for the channel will introduce additional
logic. My sense is that two functions (one that selects the web template
and calls another to retrieve the mobile equivalent of that template) is
easier to understand and test.

src/components/account-not-found/account-not-found-controller.ts

@@ -15,19 +15,18 @@ import {
 import { USER_JOURNEY_EVENTS } from "../common/state-machine/state-machine";
 import xss from "xss";
 import { getServiceSignInLink } from "../../config";
+import { getChannelSpecificTemplate } from "../../utils/get-channel-specific-template";
+import { getAccountNotFoundWebTemplate } from "./get-account-not-found-web-template";
 
 export function accountNotFoundGet(req: Request, res: Response): void {
-  if (req.session.client.isOneLoginService) {
-    res.render("account-not-found/index-one-login.njk", {
-      email: req.session.user.email,
-    });
-  } else if (req.session.client.serviceType === SERVICE_TYPE.OPTIONAL) {
-    res.render("account-not-found/index-optional.njk");
-  } else {
-    res.render("account-not-found/index-mandatory.njk", {
-      email: req.session.user.email,
-    });
-  }
+  const webTemplate: string = getAccountNotFoundWebTemplate(
+    req.session.client.isOneLoginService,
+    req.session.client.serviceType
+  );
+
+  res.render(webTemplate, {
+    email: req.session.user.email,
+  });
 }
 
 export function accountNotFoundPost(

src/components/account-not-found/get-account-not-found-web-template.ts

@@ -0,0 +1,16 @@
+import { SERVICE_TYPE } from "../../app.constants";
+
+export function getAccountNotFoundWebTemplate(
+  isOneLoginService: boolean,
+  serviceType: string
+): string {
+  if (isOneLoginService === true) {
+    return "account-not-found/index-one-login.njk";
+  }
+
+  if (serviceType === SERVICE_TYPE.OPTIONAL) {
+    return "account-not-found/index-optional.njk";
+  }
+
+  return "account-not-found/index-mandatory.njk";
+}

src/components/account-not-found/tests/get-account-not-found-web-template.test.ts

@@ -0,0 +1,32 @@
+import { expect } from "chai";
+import { describe } from "mocha";
+import { getAccountNotFoundWebTemplate } from "../get-account-not-found-web-template";
+import { SERVICE_TYPE } from "../../../app.constants";
+
+describe("getAccountNotFoundWebTemplate", () => {
+  describe("when isOneLoginService is true", () => {
+    it("should always return 'account-not-found/index-one-login.njk'", () => {
+      [SERVICE_TYPE.OPTIONAL, SERVICE_TYPE.MANDATORY].forEach((i) => {
+        expect(getAccountNotFoundWebTemplate(true, i)).to.equal(
+          "account-not-found/index-one-login.njk"
+        );
+      });
+    });
+  });
+
+  describe("when isOneLoginService is false", () => {
+    it("should return 'account-not-found/index-optional.njk' when serviceType is equal to SERVICE_TYPE.OPTIONAL", () => {
+      expect(
+        getAccountNotFoundWebTemplate(false, SERVICE_TYPE.OPTIONAL)
+      ).to.equal("account-not-found/index-optional.njk");
+    });
+
+    it("should return 'account-not-found/index-mandatory.njk' when serviceType is not equal to SERVICE_TYPE.OPTIONAL", () => {
+      [SERVICE_TYPE.MANDATORY, ""].forEach((i) => {
+        expect(getAccountNotFoundWebTemplate(false, i)).to.equal(
+          "account-not-found/index-mandatory.njk"
+        );
+      });
+    });
+  });
+});