Add support for stable prefixes for MSC2285 (#2524)

Co-authored-by: Travis Ralston <travisr@matrix.org>

spec/unit/utils.spec.ts

@@ -15,6 +15,7 @@ import {
 import { logger } from "../../src/logger";
 import { mkMessage } from "../test-utils/test-utils";
 import { makeBeaconEvent } from "../test-utils/beacon";
+import { ReceiptType } from "../../src/@types/read_receipts";
 
 // TODO: Fix types throughout
 
@@ -523,4 +524,54 @@ describe("utils", function() {
             ).toEqual([beaconEvent2, beaconEvent1, beaconEvent3]);
         });
     });
+
+    describe('getPrivateReadReceiptField', () => {
+        it('should return m.read.private if server supports stable', async () => {
+            expect(await utils.getPrivateReadReceiptField({
+                doesServerSupportUnstableFeature: jest.fn().mockImplementation((feature) => {
+                    return feature === "org.matrix.msc2285.stable";
+                }),
+            } as any)).toBe(ReceiptType.ReadPrivate);
+        });
+
+        it('should return m.read.private if server supports stable and unstable', async () => {
+            expect(await utils.getPrivateReadReceiptField({
+                doesServerSupportUnstableFeature: jest.fn().mockImplementation((feature) => {
+                    return ["org.matrix.msc2285.stable", "org.matrix.msc2285"].includes(feature);
+                }),
+            } as any)).toBe(ReceiptType.ReadPrivate);
+        });
+
+        it('should return org.matrix.msc2285.read.private if server supports  unstable', async () => {
+            expect(await utils.getPrivateReadReceiptField({
+                doesServerSupportUnstableFeature: jest.fn().mockImplementation((feature) => {
+                    return feature === "org.matrix.msc2285";
+                }),
+            } as any)).toBe(ReceiptType.UnstableReadPrivate);
+        });
+
+        it('should return none if server does not support either', async () => {
+            expect(await utils.getPrivateReadReceiptField({
+                doesServerSupportUnstableFeature: jest.fn().mockResolvedValue(false),
+            } as any)).toBeFalsy();
+        });
+    });
+
+    describe('isSupportedReceiptType', () => {
+        it('should support m.read', () => {
+            expect(utils.isSupportedReceiptType(ReceiptType.Read)).toBeTruthy();
+        });
+
+        it('should support m.read.private', () => {
+            expect(utils.isSupportedReceiptType(ReceiptType.ReadPrivate)).toBeTruthy();
+        });
+
+        it('should support org.matrix.msc2285.read.private', () => {
+            expect(utils.isSupportedReceiptType(ReceiptType.UnstableReadPrivate)).toBeTruthy();
+        });
+
+        it('should not support other receipt types', () => {
+            expect(utils.isSupportedReceiptType("this is a receipt type")).toBeFalsy();
+        });
+    });
 });