feat!: replace mlh-tsd with tsd-lite

.eslintignore

@@ -0,0 +1,4 @@
+.yarn
+build
+coverage
+e2e/__fixtures__/errors-syntax

LICENSE.md

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) Jest Community
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

@@ -1,84 +1,90 @@
-# `jest-runner-tsd`
+# jest-runner-tsd
 
-A Jest runner that tests typescript typings using [tsd](https://github.com/SamVerschueren/tsd) under the hood.
+> Run your TypeScript type tests using Jest.
 
-## Install
+[![version](https://img.shields.io/npm/v/jest-runner-tsd.svg)](https://npmjs.com/package/jest-runner-tsd)
+[![license](https://img.shields.io/github/license/jest-community/jest-runner-tsd.svg)](https://github.com/jest-community/jest-runner-tsd/blob/main/LICENSE.md)
 
-Install `jest-runner-tsd`
+**Note:** the `jest-runner-tsd` is using [`tsd-lite`](https://github.com/mrazauskas/tsd-lite) instead of [`tsd`](https://github.com/SamVerschueren/tsd). Both of them have the same type testing logic, but `tsd-light` makes it easier to test projects written in TypeScript (or types generated by your library).
 
-```bash
-yarn add --dev jest-runner-tsd
+Most important differences (for the full list see [`tsd-lite` repo](https://github.com/mrazauskas/tsd-lite)):
+
+- `tsd-lite` has no additional [rules](https://github.com/SamVerschueren/tsd/issues/32) or checks;
+- `jest.config` is used to discover test files;
+- and `tsconfig.json` provides configuration for TS compiler. For details see [Configuration](#configuration) section.
 
-# or with NPM
+## Install
 
-npm install --save-dev jest-runner-tsd
+```bash
+yarn add -D jest-runner-tsd @tsd/typescript
 ```
 
-### Adding to Jest Config
+Remember to install `@tsd/typescript` package. It is a required peer dependency.
+
+## Configuration
 
-Create a `jest.config.types.js` file and have the runner property set to `jest-runner-tsd` as shown below:
+### Jest
+
+First of all, you should [configure Jest](https://jestjs.io/docs/configuration) to discover your test files. For example, if the files are suffix with `.test.ts` and live inside `__typetests__` directory, set up `jest.config.tsd.js` like this:
 
 ```js
 module.exports = {
+  displayName: {
+    color: 'blue',
+    name: 'types',
+  },
   runner: 'jest-runner-tsd',
+  testMatch: ['**/__typetests__/*.test.ts'],
 };
 ```
 
-In the project `package.json` file, modify the scripts block to use the configuration file as show below:
+### TS Compiler
 
-```json
-...
-"scripts": {
-  ...
-  "type-tests": "yarn jest --config jest.config.types.js"
-}
-...
-```
+Your test files will be compiled using the [TypeScript compiler](https://github.com/microsoft/TypeScript/wiki/Using-the-Compiler-API) (similarly to `tsc`), but, instead of emitting JS code, `tsd-lite` will analyze types and diagnostics returned by the compiler.
 
-### Run
+To compile each test file, `tsd-lite` will read the nearest [`tsconfig.json`](https://www.typescriptlang.org/docs/handbook/tsconfig-json.html) and will pass the configuration to the compiler. Hence, you may have a configuration for the whole project, or a group of test files, or just a particular test file.
 
-To start the test, just execute the following command
+For example, if your project already includes a `tsconfig.json` in the root directory, but you prefer to have different configuration for testing, simply add another `tsconfig.json` to a directory with the test files. It may override or extend your root configuration.
 
-```bash
-yarn test-types
-```
-
-## Writing tests
+**Hint:** run `yarn tsc -p path/to/__typetests__ --showConfig` to print the configuration which applies to the test files.
 
-> This runner uses TSD. To see the available assertions, checkout it's [documentation](https://github.com/SamVerschueren/tsd)
+**Note:** if `tsconfig.json` is not found, the compiler will fall back to the default configuration.
 
-### For JavaScript Projects
+### Optionally Strict
 
-There are multiple ways you can pass a type definition file.
+Just like TypeScript, `tsd-lite` is [optionally strict](https://www.typescriptlang.org/docs/handbook/2/basic-types.html#strictness). In contrary, the vanilla `tsd` is strict by default. If you are migrating your test suite, remember to set `"strict": true` in `tsconfig.json`.
 
-#### Default
+```ts
+import { expectType } from 'tsd-lite';
 
-The type definitions should be in a file named `index.d.ts` in the root directory of the project by default.
+declare const loggedInUsername: string;
 
-#### `types` property in package.json
+const users = [
+  { name: 'Oby', age: 12 },
+  { name: 'Heera', age: 32 },
+];
 
-You can also set your `types` property in package.json. The runner will automatically pick the type defintion file from there.
+const loggedInUser = users.find(u => u.name === loggedInUsername);
 
-```json
-{
-  ...
-  "types": "path/to/types.d.ts"
-}
+expectType<number>(loggedInUser.age);
 ```
 
-#### Docblocks
+The assertion in this example fails with `"strict": true`, but passes with `"strict": false`.
 
-If the type definition file is located somewhere else then specify its path in the top of respective test file using the `@type` inside a docblock.
+## Running Tests
 
-```ts
-/**
- * @type ../../custom/path/to/types.d.ts
- **/
+If all is set, simply run `yarn jest -c jest.config.tsd.js` command. Or better include a script in `package.json`:
+
+```json
+"scripts": {
+  "test:types": "jest -c jest.config.tsd.js"
+}
 ```
 
-### For TypeScript Projects
+## Learn More
+
+To learn more about `tsd` and its assertions see the [documentation](https://github.com/SamVerschueren/tsd).
 
-> **Note:** This is only a workaround. A stable solution may be introduced in future.
+## License
 
-Due to [limitations in TSD](https://github.com/SamVerschueren/tsd/issues/32), the only solution now for testing types in TypeScript projects
-would be to have a empty type definition file and specify it's path using one of the many methods explained above.
+[MIT](https://github.com/jest-community/jest-runner-tsd/blob/main/LICENSE.md) © Jest Community

e2e/__fixtures__/errors-syntax/index.d.ts

@@ -0,0 +1,7 @@
+/* eslint-disable no-unused-vars */
+declare const one: {
+  (foo: string, bar: string): string;
+  (foo: number, bar: number): number;
+};
+
+export default one;

e2e/__fixtures__/errors-syntax/index.js

@@ -0,0 +1,3 @@
+module.exports.default = (foo, bar) => {
+  return foo + bar;
+};

e2e/__fixtures__/errors-syntax/index.test.ts

@@ -0,0 +1,5 @@
+import { expectError } from 'tsd-lite';
+import one from '.';
+
+expectError(one('foo', 'bar');
+expectError(one('foo' 'bar'));

e2e/__fixtures__/errors-syntax/package.json

@@ -0,0 +1,8 @@
+{
+  "jest": {
+    "runner": "../../../src/",
+    "testMatch": [
+      "**/*.test.ts"
+    ]
+  }
+}

e2e/__fixtures__/errors-tsconfig/index.test.ts

@@ -0,0 +1,3 @@
+import { expectType } from 'tsd-lite';
+
+expectType<string>('dummy test');

e2e/__fixtures__/errors-tsconfig/package.json

@@ -0,0 +1,8 @@
+{
+  "jest": {
+    "runner": "../../../src/",
+    "testMatch": [
+      "**/*.test.ts"
+    ]
+  }
+}

e2e/__fixtures__/errors-tsconfig/tsconfig.json

@@ -0,0 +1,9 @@
+{
+  "compilerOptions": {
+    "module": "commonjs",
+    "target": "es2019",
+    "strict": "yes",
+    "noEmitOnError": true
+  },
+  "include": ["./**/*"]
+}

e2e/__fixtures__/failing/index.test.ts → e2e/__fixtures__/js-failing/index.test.ts

@@ -1,4 +1,4 @@
-import { expectType } from 'mlh-tsd';
+import { expectType } from 'tsd-lite';
 import concat from '.';
 
 expectType<string>(concat('pre', 'fix'));

e2e/__fixtures__/passing/index.test.ts → e2e/__fixtures__/js-passing/index.test.ts

@@ -1,4 +1,4 @@
-import { expectType } from 'mlh-tsd';
+import { expectType } from 'tsd-lite';
 import concat from '.';
 
 expectType<string>(concat('pre', 'fix'));

e2e/__fixtures__/override-tsconfig/index.test.ts

@@ -0,0 +1,14 @@
+// Adapted from: https://www.typescriptlang.org/tsconfig#strictNullChecks
+
+import { expectType } from 'tsd-lite';
+
+declare const loggedInUsername: string;
+
+const users = [
+  { name: 'Oby', age: 12 },
+  { name: 'Heera', age: 32 },
+];
+
+const loggedInUser = users.find(u => u.name === loggedInUsername);
+
+expectType<number>(loggedInUser.age);

e2e/__fixtures__/override-tsconfig/tsconfig.json

@@ -0,0 +1,7 @@
+{
+  "extends": "../../tsconfig.json",
+  "compilerOptions": {
+    "strict": false
+  },
+  "include": ["**/*"]
+}

e2e/__fixtures__/ts-failing/index.test.ts

@@ -0,0 +1,8 @@
+import { expectError, expectType } from 'tsd-lite';
+import { makeDate } from '.';
+
+expectType<Date>(makeDate(12345678));
+expectType<string>(makeDate(5, 5, 5));
+
+expectError(makeDate(1, 3, 6));
+expectError(makeDate(1, 3));

e2e/__fixtures__/ts-failing/index.ts

@@ -0,0 +1,13 @@
+/* eslint-disable no-unused-vars */
+
+function makeDate(timestamp: number): Date;
+function makeDate(m: number, d: number, y: number): Date;
+function makeDate(mOrTimestamp: number, d?: number, y?: number): Date {
+  if (d !== undefined && y !== undefined) {
+    return new Date(y, mOrTimestamp, d);
+  } else {
+    return new Date(mOrTimestamp);
+  }
+}
+
+export { makeDate };

e2e/__fixtures__/pkg-types/package.json → e2e/__fixtures__/ts-failing/package.json

@@ -1,5 +1,4 @@
 {
-  "types": "./types.d.ts",
   "jest": {
     "runner": "../../../src/",
     "testMatch": ["**/*.test.ts"]

e2e/__fixtures__/ts-passing/index.test.ts

@@ -0,0 +1,12 @@
+import { expectError, expectType } from 'tsd-lite';
+
+interface SomeType {
+  readonly prop: string;
+}
+
+function doSomething(obj: SomeType) {
+  expectError((obj.prop = 'hello'));
+  return obj.prop;
+}
+
+expectType<string>(doSomething({ prop: 'val' }));

e2e/__fixtures__/ts-passing/package.json

@@ -0,0 +1,6 @@
+{
+  "jest": {
+    "runner": "../../../src/",
+    "testMatch": ["**/*.test.ts"]
+  }
+}

e2e/__snapshots__/errors.test.ts.snap

@@ -0,0 +1,40 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`throws if nearest tsconfig.json is not valid 1`] = `
+"FAIL e2e/__fixtures__/errors-tsconfig/index.test.ts
+  ● Test suite failed to run
+    ConfigError: Compiler option 'strict' requires a value of type boolean.
+      3 |     \\"module\\": \\"commonjs\\",
+      4 |     \\"target\\": \\"es2019\\",
+    > 5 |     \\"strict\\": \\"yes\\",
+        |               ^
+      6 |     \\"noEmitOnError\\": true
+      7 |   },
+      8 |   \\"include\\": [\\"./**/*\\"]
+      at tsconfig.json:5:15
+Test Suites: 1 failed, 1 total
+Tests:       0 total
+Snapshots:   0 total
+Time:
+Ran all test suites.
+"
+`;
+
+exports[`throws if syntax error is encountered 1`] = `
+"FAIL e2e/__fixtures__/errors-syntax/index.test.ts
+  ● Test suite failed to run
+    SyntaxError: ')' expected.
+      2 | import one from '.';
+      3 |
+    > 4 | expectError(one('foo', 'bar');
+        |                              ^
+      5 | expectError(one('foo' 'bar'));
+      6 |
+      at index.test.ts:4:30
+Test Suites: 1 failed, 1 total
+Tests:       0 total
+Snapshots:   0 total
+Time:
+Ran all test suites.
+"
+`;