Use sha256 for access tokens

tests/access_tokens.test.ts

@@ -5,6 +5,8 @@ import {
   AccessTokenPerAuthToken,
   EncryptedAccessTokens,
   ExpiringAccessTokens,
+  InMemoryAccessTokens,
+  sha256
 } from "../src/access_tokens";
 import { Encryption } from "../src/encryption";
 
@@ -207,5 +209,65 @@ describe("AccessTokenPerAuthToken", () => {
       expect(accessTokens.authTokenFor(uuid())).toBeUndefined();
     });
   });
-
+});
+
+describe('sha256 minter', () => {
+  it('should return the same value for the same salt and authToken', () => {
+    const authToken = uuid();
+    const token1 = sha256("salty")(authToken);
+    const token2 = sha256("salty")(authToken);
+
+    expect(token1).not.toEqual(authToken);
+    expect(token1).toEqual(token2);
+  });
+
+  it('should returrn different values for the same salt but different authTokens', () => {
+    const authToken1 = uuid();
+    const authToken2 = uuid();
+
+    const token1 = sha256("salty")(authToken1);
+    const token2= sha256("salty")(authToken2);
+
+    expect(token1).not.toEqual(token2);
+  });
+
+  it('should return different values for the same authToken but different salts', () => {
+    const authToken = uuid();
+
+    const token1 = sha256("salt1")(authToken);
+    const token2= sha256("salt2")(authToken);
+
+    expect(token1).not.toEqual(token2);
+  });
+});
+
+describe("InMemoryAccessTokens", () => {
+  const reverseAuthToken = (authToken: string) => authToken.split("").reverse().join("");
+
+  const accessTokens = new InMemoryAccessTokens(reverseAuthToken);
+
+  it("should return the same access token for the same auth token", () => {
+    const authToken = "token1";
+    
+    const accessToken1 = accessTokens.mint(authToken);
+    const accessToken2 = accessTokens.mint(authToken);
+
+    expect(accessToken1).not.toEqual(authToken);
+    expect(accessToken1).toEqual(accessToken2);
+  });
+
+  describe("when there is an auth token for the access token", () => {
+    it("should be able to retrieve it", () => {
+      const authToken = uuid();
+      const accessToken = accessTokens.mint(authToken);
+
+      expect(accessTokens.authTokenFor(accessToken)).toEqual(authToken);
+    });
+  });
+
+  describe("when there is no auth token for the access token", () => {
+    it("should return undefined", () => {
+      expect(accessTokens.authTokenFor(uuid())).toBeUndefined();
+    });
+  });
 });