chore: initial commit

implement jest and sinon versions of mocks

Author: maxjoehnk

.gitignore

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+node_modules
+yarn.lock
+*.js
+*.d.ts
+!jest.config.js
+!.eslintrc.js

README.md

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+# proxy-mocks
+
+Generate mocks for any class or object.
+
+## Example
+
+```typescript
+// import { IMock, Mock } from 'proxy-mocks/jest';
+import { IMock, Mock } from "proxy-mocks/sinon";
+import Dependency from "./dependency";
+import Implementation from "./implementation";
+
+describe("Implementation", () => {
+  let dependency: IMock<Dependency>;
+
+  let implementation: Implementation;
+
+  beforeEach(() => {
+    dependency = Mock.of(Dependency);
+
+    implementation = new Implementation(dependency);
+  });
+
+  test("your test", () => {
+    dependency.someMethod.returns("your result");
+
+    const result = implementation.anotherMethod();
+
+    expect(result).toEqual("your result");
+  });
+});
+```

dprint.json

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+{
+  "$schema": "https://dprint.dev/schemas/v0.json",
+  "projectType": "openSource",
+  "incremental": true,
+  "typescript": {
+    "indentWidth": 2
+  },
+  "json": {
+  },
+  "markdown": {
+  },
+  "includes": ["**/*.{ts,tsx,js,jsx,json,md}"],
+  "excludes": [
+    "**/node_modules",
+    "**/*-lock.json",
+    "src/**/*.js",
+    "**/*.d.ts"
+  ],
+  "plugins": [
+    "https://plugins.dprint.dev/typescript-0.44.0.wasm",
+    "https://plugins.dprint.dev/json-0.10.1.wasm",
+    "https://plugins.dprint.dev/markdown-0.6.2.wasm"
+  ]
+}

package.json

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+{
+  "name": "proxy-mocks",
+  "version": "0.1.0",
+  "description": "Provide mocks utilizing the Proxy API",
+  "main": "index.js",
+  "repository": "https://github.com/maxjoehnk/proxy-mocks",
+  "author": "Max Jöhnk <[email protected]>",
+  "license": "MIT",
+  "scripts": {
+    "clean": "rimraf '*.{d.ts,js}'",
+    "prebuild": "npm run clean",
+    "build": "tsc --outDir .",
+    "test": "jest",
+    "lint": "eslint src --ext .ts",
+    "prepare": "npm run check",
+    "prepack": "npm run check",
+    "format": "dprint fmt",
+    "format.check": "dprint check",
+    "check": "npm run build && npm run lint && npm run test"
+  },
+  "files": [
+    "README.md",
+    "jest.js",
+    "sinon.js",
+    "mock.js",
+    "index.js"
+  ],
+  "peerDependencies": {
+    "jest": "^26.6.3",
+    "sinon": "^10.0.1"
+  },
+  "devDependencies": {
+    "@types/jest": "^26.0.22",
+    "@types/sinon": "^9.0.11",
+    "@typescript-eslint/eslint-plugin": "^4.21.0",
+    "@typescript-eslint/parser": "^4.21.0",
+    "eslint": "^7.23.0",
+    "jest": "^26.6.3",
+    "rimraf": "^3.0.2",
+    "sinon": "^10.0.1",
+    "ts-jest": "^26.5.4",
+    "typescript": "^4.2.4"
+  },
+  "jest": {
+    "moduleFileExtensions": [
+      "ts",
+      "js",
+      "json"
+    ],
+    "testMatch": [
+      "<rootDir>/src/**/*.test.ts"
+    ],
+    "preset": "ts-jest",
+    "globals": {
+      "ts-jest": {
+        "tsconfig": "tsconfig.test.json"
+      }
+    }
+  },
+  "eslintConfig": {
+    "root": true,
+    "parser": "@typescript-eslint/parser",
+    "plugins": [
+      "@typescript-eslint"
+    ],
+    "extends": [
+      "eslint:recommended",
+      "plugin:@typescript-eslint/recommended"
+    ],
+    "rules": {
+      "@typescript-eslint/no-explicit-any": 0,
+      "@typescript-eslint/ban-types": 0
+    }
+  }
+}

src/index.ts

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+export * as jest from "./jest";
+export * as sinon from "./sinon";

src/jest.test.ts

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+import { Mock } from "./jest";
+import { TestServiceToMock } from "./test-utils";
+
+describe("Jest Mocks", () => {
+  test("accessing a method should create a stub for it", () => {
+    const mock = Mock.of(TestServiceToMock);
+
+    const isStub = jest.isMockFunction(mock.someMethod);
+
+    expect(isStub).toBe(true);
+  });
+});

src/jest.ts

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+import { createMockImplementationWithStubFunction, MockableObject, MockPrototype } from "./mock";
+
+import * as base from "./mock";
+
+/**
+ * Mocked object with stubs generated with jest
+ */
+export type IMock<TObject extends MockableObject> = base.IMock<TObject, jest.Mock<TObject>>;
+
+export const Mock: MockPrototype<jest.Mock> = createMockImplementationWithStubFunction(jest.fn);

src/mock.ts

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+export type RecursivePartial<T> = Partial<
+  {
+    [key in keyof T]: T[key] extends (...a: Array<infer U>) => unknown
+      ? (...a: Array<U>) => RecursivePartial<ReturnType<T[key]>> | ReturnType<T[key]> // tslint:disable-line
+      : T[key] extends Array<unknown> ? Array<RecursivePartial<T[key][number]>>
+      : RecursivePartial<T[key]> | T[key];
+  }
+>;
+
+/**
+ * Mock object with generated stubs.
+ *
+ * There is no guarantee whether a property is actually a stub or not as it can be overridden at creation time.
+ */
+export type IMock<TObject extends MockableObject, TStub> = TObject & { [P in keyof TObject]: TStub };
+
+/**
+ * Generate new mock class using given {@param stubFunction} to generate stubs
+ */
+export function createMockImplementationWithStubFunction<TStub>(stubFunction: () => TStub): MockPrototype<TStub> {
+  return class Mock {
+    /**
+     * Generate a new mock for the given class.
+     *
+     * @param clazz the class to generate a mock for.
+     * @param overrides can be used to set properties. They will not be replaced with stubs.
+     */
+    public static of<TObject extends MockableObject>(
+      clazz: Clazz<TObject> = null,
+      overrides: RecursivePartial<TObject> = {},
+    ): IMock<TObject, TStub> {
+      return new Proxy<IMock<TObject, TStub>>(overrides as any, {
+        get(target: IMock<TObject, TStub>, key: PropertyKey) {
+          // Angular tries to create a Set of a provided value via the following code
+          //
+          // ```javascript
+          // var QUOTED_KEYS = '$quoted$';
+          // var quotedSet = new Set(map && map[QUOTED_KEYS]);
+          // ```
+          //
+          // This fails when $quoted$ is a stub, so we explicitly return undefined here
+          if (key === "$quoted$") {
+            return undefined;
+          }
+          // TODO: allow configuration of Mock as a Promise
+          if (key === "then") {
+            return undefined;
+          }
+          const name: keyof TObject = key as any;
+          if (target[name] === undefined) {
+            target[name] = stubFunction() as any;
+          }
+          return target[name];
+        },
+        getPrototypeOf(): MockableObject | null {
+          return clazz?.prototype ?? null;
+        },
+      });
+    }
+
+    /**
+     * Generate new mock without setting the prototype (for e.g. a Typescript interface)
+     *
+     * {@param overrides} can be used to set properties. They will not be replaced with stubs.
+     */
+    public static with<TObject extends MockableObject>(
+      overrides: RecursivePartial<TObject> = {},
+    ): IMock<TObject, TStub> {
+      return Mock.of<TObject>(null, overrides);
+    }
+  };
+}
+
+interface Clazz<T> extends Function {
+  new(...args: any[]): T;
+}
+
+export interface MockPrototype<TStub> {
+  /**
+   * Generate a new mock for the given class.
+   *
+   * @param clazz the class to generate a mock for.
+   * @param overrides can be used to set properties. They will not be replaced with stubs.
+   */
+  of<TObject extends MockableObject>(
+    clazz: Clazz<TObject>,
+    overrides?: RecursivePartial<TObject>,
+  ): IMock<TObject, TStub>;
+
+  /**
+   * Generate new mock without setting the prototype (for e.g. a Typescript interface)
+   *
+   * {@param overrides} can be used to set properties. They will not be replaced with stubs.
+   */
+  with<TObject extends MockableObject>(overrides: RecursivePartial<TObject>): IMock<TObject, TStub>;
+}
+
+export type MockableObject = object;

src/sinon.test.ts

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+import { SinonStub } from "sinon";
+import { Mock } from "./sinon";
+import { TestServiceToMock } from "./test-utils";
+
+describe("Sinon Mocks", () => {
+  test("accessing a method should create a stub for it", () => {
+    const mock = Mock.of(TestServiceToMock);
+
+    const isStub = isSinonStub(mock.someMethod);
+
+    expect(isStub).toBe(true);
+  });
+});
+
+function isSinonStub(stub: SinonStub): boolean {
+  // implementation detail of sinon
+  // sinon sets the isSinonProxy to true when it creates a stub
+  return (stub as any).isSinonProxy;
+}

src/sinon.ts

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+import { SinonStub, stub } from "sinon";
+import { createMockImplementationWithStubFunction, MockPrototype } from "./mock";
+
+import * as base from "./mock";
+
+/**
+ * Mock object with generated stubs.
+ *
+ * There is no guarantee whether a property is actually a stub or not as it can be overridden at creation time.
+ */
+export type IMock<TObject extends base.MockableObject> = base.IMock<TObject, SinonStub>;
+
+export const Mock: MockPrototype<SinonStub> = createMockImplementationWithStubFunction(stub);