Move utility tests to the right place

test/utils/Singleflight-test.ts

@@ -0,0 +1,115 @@
+/*
+Copyright 2021 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import {Singleflight} from "../../src/utils/Singleflight";
+
+describe('Singleflight', () => {
+    afterEach(() => {
+        Singleflight.forgetAll();
+    });
+
+    it('should throw for bad context variables', () => {
+        const permutations: [Object, string][] = [
+            [null, null],
+            [{}, null],
+            [null, "test"],
+        ];
+        for (const p of permutations) {
+            try {
+                Singleflight.for(p[0], p[1]);
+                // noinspection ExceptionCaughtLocallyJS
+                throw new Error("failed to fail: " + JSON.stringify(p));
+            } catch (e) {
+                expect(e.message).toBe("An instance and key must be supplied");
+            }
+        }
+    });
+
+    it('should execute the function once', () => {
+        const instance = {};
+        const key = "test";
+        const val = {}; // unique object for reference check
+        const fn = jest.fn().mockReturnValue(val);
+        const sf = Singleflight.for(instance, key);
+        const r1 = sf.do(fn);
+        expect(r1).toBe(val);
+        expect(fn.mock.calls.length).toBe(1);
+        const r2 = sf.do(fn);
+        expect(r2).toBe(val);
+        expect(fn.mock.calls.length).toBe(1);
+    });
+
+    it('should execute the function once, even with new contexts', () => {
+        const instance = {};
+        const key = "test";
+        const val = {}; // unique object for reference check
+        const fn = jest.fn().mockReturnValue(val);
+        let sf = Singleflight.for(instance, key);
+        const r1 = sf.do(fn);
+        expect(r1).toBe(val);
+        expect(fn.mock.calls.length).toBe(1);
+        sf = Singleflight.for(instance, key); // RESET FOR TEST
+        const r2 = sf.do(fn);
+        expect(r2).toBe(val);
+        expect(fn.mock.calls.length).toBe(1);
+    });
+
+    it('should execute the function twice if the result was forgotten', () => {
+        const instance = {};
+        const key = "test";
+        const val = {}; // unique object for reference check
+        const fn = jest.fn().mockReturnValue(val);
+        const sf = Singleflight.for(instance, key);
+        const r1 = sf.do(fn);
+        expect(r1).toBe(val);
+        expect(fn.mock.calls.length).toBe(1);
+        sf.forget();
+        const r2 = sf.do(fn);
+        expect(r2).toBe(val);
+        expect(fn.mock.calls.length).toBe(2);
+    });
+
+    it('should execute the function twice if the instance was forgotten', () => {
+        const instance = {};
+        const key = "test";
+        const val = {}; // unique object for reference check
+        const fn = jest.fn().mockReturnValue(val);
+        const sf = Singleflight.for(instance, key);
+        const r1 = sf.do(fn);
+        expect(r1).toBe(val);
+        expect(fn.mock.calls.length).toBe(1);
+        Singleflight.forgetAllFor(instance);
+        const r2 = sf.do(fn);
+        expect(r2).toBe(val);
+        expect(fn.mock.calls.length).toBe(2);
+    });
+
+    it('should execute the function twice if everything was forgotten', () => {
+        const instance = {};
+        const key = "test";
+        const val = {}; // unique object for reference check
+        const fn = jest.fn().mockReturnValue(val);
+        const sf = Singleflight.for(instance, key);
+        const r1 = sf.do(fn);
+        expect(r1).toBe(val);
+        expect(fn.mock.calls.length).toBe(1);
+        Singleflight.forgetAll();
+        const r2 = sf.do(fn);
+        expect(r2).toBe(val);
+        expect(fn.mock.calls.length).toBe(2);
+    });
+});
+