original file name: Codeium Chat - kVFsnKWa1O6kJKQ87R8jHMjsxZu22Qke.md summary: The chat covers the user's need to add tests to a TypeScript terminal app, where they encounter issues such as errors related to construct signatures, missing semicolons, and the document object not being defined.

I provide guidance on setting up testing frameworks like Jest, writing tests to verify command history updates, and configuring Jest to use the `jsdom` environment for browser-like APIs. Additionally, I address errors related to TypeScript parsing, suggest checking Jest configurations, and provide steps to troubleshoot and resolve issues with TypeScript transformations and configurations in Jest. date: 2024-05-01T13:56

Codeium Chat Conversation

Note: This is purely the output of the chat conversation and does not contain any raw data, codebase snippets, etc. used to generate the output.

User at 1:56 pm, May 1, 2024

I need to start adding tests to my TypeScript terminal app in assets/ts/terminal/

How can I start?

Codeium at 1:56 pm, May 1, 2024

To start adding tests to your TypeScript terminal app, you can follow these steps:

Choose a Testing Framework: Popular testing frameworks for TypeScript include Jest, Mocha, and Jasmine. Jest is widely used and comes with its own assertion library.
Install the Testing Framework: For Jest, you can install it with npm:
```
npm install --save-dev jest @types/jest ts-jest
```
Configure the Testing Framework: For Jest, initialize the configuration:
```
npx jest --init
```
In the configuration file (jest.config.js), make sure to set it up for TypeScript by specifying the preset to ts-jest.
```
module.exports = {
  preset: 'ts-jest',
  testEnvironment: 'node',
  // other configuration options
};
```

Write Your Tests: Create test files next to your TypeScript files or in a separate test directory. By convention, Jest looks for files with .test.ts or .spec.ts suffixes.

Here's an example of how you might write a test for a function in your XtermAdapter class:

// XtermAdapter.test.ts
import { XtermAdapter } from './XtermAdapter';

describe('XtermAdapter', () => {
  let xtermAdapter: XtermAdapter;

  beforeEach(() => {
    // Set up your test environment
    // Mock any necessary constructors or methods
    const mockElement = document.createElement('div');
    const mockHandexTerm = /* Mock implementation */;
    xtermAdapter = new XtermAdapter(mockHandexTerm, mockElement);
  });

  it('should create output element on construction', () => {
    expect(xtermAdapter.outputElement).toBeDefined();
  });

  // Add more tests as necessary
});

Run Your Tests: Run your tests using the npm script provided by Jest:
```
npm test
```
Or directly with Jest:
```
npx jest
```
Continuously Run Tests in Watch Mode: To run your tests continuously during development, use Jest's watch mode:
```
npx jest --watch
```

Remember to mock any dependencies, such as DOM elements or other classes that your XtermAdapter interacts with. This will isolate your tests and ensure they only test the functionality of the XtermAdapter class itself.

If you need further assistance with setting up tests or writing test cases, feel free to ask!

User at 2:12 pm, May 1, 2024

I am getting this error:

This expression is not constructable.
  Type 'XtermAdapter' has no construct signatures.ts(2351)

Codeium at 2:13 pm, May 1, 2024

The error message suggests that TypeScript is interpreting XtermAdapter as a value rather than a type, and it's trying to treat it as a class or function that can be instantiated, but it fails because there's no construct signature available. This can happen if XtermAdapter is not exported as a class or if the import is incorrect.

Based on the selected code snippet from XtermAdapter.test.ts, it looks like there may be an issue with how the XtermAdapter class is being imported or used. Here's a potential mistake in the test code:

let XtermAdapter: XtermAdapter;

This line is declaring a variable XtermAdapter with a type XtermAdapter, which shadows the class name XtermAdapter. This can cause confusion for TypeScript's type system.

To fix the issue, you should change the variable name to something that does not shadow the class name, typically using camelCase for instance variables:

let xtermAdapter: XtermAdapter;

Then, make sure to instantiate the XtermAdapter class correctly:

beforeEach(() => {
    const mockElement = document.createElement('div');
    mockElement.classList.add('terminal');
    const mockHandexTerm = {
        output: (data: string) => {},
        getCommandHistory: () => [],
        handleCommand: (data: string) => {},
        handleCharacter: (data: string) => 0
    };
    
    // Corrected variable name to camelCase
    xtermAdapter = new XtermAdapter(mockHandexTerm, mockElement);
});

Ensure that the XtermAdapter class is exported properly in the XtermAdapter.ts file:

export class XtermAdapter {
  // Class implementation...
}

After making these changes, the error should be resolved. If the issue persists, please check the actual export statement in the XtermAdapter.ts file and ensure that there are no typos or incorrect paths in the import statement.

User at 2:23 pm, May 1, 2024

Ok, now I would like to create a test that verifies that every time the user types in a command and hits Enter, that a command element is added to the commandHistory and that added command element contains the text of the command.

how can I do that?

Codeium at 2:24 pm, May 1, 2024

To create a test that verifies commands are added to the commandHistory when the user types a command and hits Enter, you'll need to simulate this behavior and check the state of commandHistory afterwards. Here's a guide on how to write such a test:

Mock Necessary Methods and Properties: In your test setup, mock the methods and properties that will be used during the test. You may need to mock methods of XtermAdapter or any dependencies that handle the command input and history.
Simulate User Input: Simulate the user typing a command and hitting Enter. This could involve calling a method on the XtermAdapter instance that processes input data, such as an onDataHandler method.
Assert Command History State: After simulating the user input, assert that the commandHistory array has been updated correctly. Check that a new element has been added and that it contains the expected command text.

Here's a hypothetical example of a test that accomplishes this:

import { XtermAdapter } from './XtermAdapter';

describe('XtermAdapter', () => {
  let xtermAdapter: XtermAdapter;
  let mockElement: HTMLDivElement;
  let mockHandexTerm: any;

  beforeEach(() => {
    mockElement = document.createElement('div');
    mockHandexTerm = {
      getCommandHistory: jest.fn(() => []),
      handleCommand: jest.fn((input: string) => {
        const commandElement = document.createElement('div');
        commandElement.textContent = input;
        return commandElement;
      }),
      handleCharacter: jest.fn((data: string) => 0)
    };
    
    xtermAdapter = new XtermAdapter(mockHandexTerm, mockElement);
  });

  it('should add command element to commandHistory when user enters a command', () => {
    // The command the user types
    const command = 'ls -al';

    // Simulate the user typing the command and hitting Enter
    // This is a simplified example; your actual implementation may differ
    xtermAdapter.onDataHandler(`${command}\r`); // Assuming '\r' is the Enter key signal

    // Check that handleCommand was called with the correct command
    expect(mockHandexTerm.handleCommand).toHaveBeenCalledWith(command);

    // Check the commandHistory to see if the command element was added
    expect(xtermAdapter.commandHistory.length).toBe(1);
    expect(xtermAdapter.commandHistory[0].textContent).toBe(command);
  });
});

Please note that the above code is hypothetical and assumes the presence of an onDataHandler method that processes incoming data as commands when the user hits Enter. You'll need to adjust the test code according to your actual implementation of XtermAdapter and the dependencies it interacts with.

The handleCommand mock is a simplified version that creates a new div element with the command text and returns it. In your actual code, handleCommand may have more complex logic and side effects.

Ensure your actual XtermAdapter class has a commandHistory property or similar to track the history of commands, and adjust the test code accordingly. If it does not have such a property, you might be checking the state of the command history in another way, such as verifying the DOM elements within mockElement.

User at 2:40 pm, May 1, 2024

I am getting this error:

Details:

  SyntaxError: D:\T3\Projects\self\handex.io\assets\ts\terminal\XtermAdapter.test.ts: Missing semicolon. (4:18)

   2 |
   3 | describe('XtermAdapter', () => {
  > 4 |  let xtermAdapter: XtermAdapter;
    |          ^
   5 |  let mockElement: HTMLDivElement;

Codeium at 2:41 pm, May 1, 2024

The error message indicates a syntax issue in XtermAdapter.test.ts at line 4. It suggests that a semicolon is missing, but TypeScript doesn't strictly require semicolons. The actual issue might be different, such as an import statement that's missing or incorrect.

To resolve the issue, check for a few things:

Ensure that you have imported XtermAdapter correctly at the top of your test file:
```
import { XtermAdapter } from './XtermAdapter';
```
Make sure that there are no syntax errors above the highlighted line, such as missing import statements or incorrect syntax.
If you're using a linter or formatter, it might be enforcing semicolons. In that case, you can add them at the end of each statement to comply with the linter's rules.

Here's how your file should start, including the import statement and the corrected use of semicolons if they are required by your linter:

import { XtermAdapter } from './XtermAdapter';

describe('XtermAdapter', () => {
  let xtermAdapter: XtermAdapter;
  let mockElement: HTMLDivElement;
  let mockHandexTerm: any;

  // ...rest of your code

Check that the rest of your code also follows the syntax rules of your project. If you continue to have trouble, please ensure that your TypeScript environment is set up correctly and that the file XtermAdapter.ts is in the correct location relative to your test file.

User at 2:42 pm, May 1, 2024

These are the results from npx jest, not a linter.

I am also getting this:

● XtermAdapter › should add command element to commandHistory when user enters a command

  The error below may be caused by using the wrong test environment, see https://jestjs.io/docs/configuration#testenvironment-string.
  Consider using the "jsdom" test environment.

  ReferenceError: document is not defined

Codeium at 2:43 pm, May 1, 2024

The error you're encountering indicates that Jest is being run in an environment that does not have access to the document object, which is typically available in a web browser.

By default, Jest uses a Node environment that is suitable for testing server-side JavaScript and does not include browser-specific APIs like document or window. However, you can configure Jest to use the jsdom environment, which simulates a browser environment.

To resolve this issue, you should set the testEnvironment option in your Jest configuration to use jsdom. You can do this by editing your jest.config.js file to include the following configuration:

module.exports = {
  // ... other configurations
  testEnvironment: 'jsdom',
};

After setting the testEnvironment to jsdom, Jest will be able to use browser-like globals such as document and window.

If you don't have a jest.config.js file or if you're using the package.json for your Jest configuration, you can add the testEnvironment option there:

"jest": {
  "testEnvironment": "jsdom",
  // ... other configurations
}

Once you've updated your Jest configuration, run your tests again with npx jest, and the document is not defined error should be resolved. If you continue to experience issues or need further assistance with your tests, feel free to ask.

User at 2:44 pm, May 1, 2024

I have a jest.config.ts, not a jest.config.js.

It has a const config: Config = { instead of a module.exports = {

Codeium at 2:45 pm, May 1, 2024

In your jest.config.ts file, which uses TypeScript, you can set the testEnvironment property to 'jsdom' within the exported config object. Since you are using TypeScript, the jest.config.ts file will likely be using ES6 module syntax with export default.

Here's how you can modify your jest.config.ts file to include the jsdom environment:

import type { Config } from 'jest';

const config: Config = {
  // ... other configurations
  testEnvironment: 'jsdom',
};

export default config;

After making this change, Jest will use the jsdom environment for your tests, which should resolve the issue with the document is not defined error. Make sure to re-run your tests using npx jest to see if the changes have taken effect.

If you continue to encounter problems, ensure that the jest.config.ts changes are saved and that there are no other conflicting configurations in your Jest setup.

User at 2:55 pm, May 1, 2024

I am still getting the colon error, and it says this:

 FAIL assets/ts/terminal/XtermAdapter.test.ts
 ● Test suite failed to run

  Jest encountered an unexpected token

  Jest failed to parse a file. This happens e.g. when your code or its dependencies use non-standard JavaScript syntax, or when Jest is not configured to support such syntax.

  Out of the box Jest supports Babel, which will be used to transform your files into valid JS based on your Babel configuration.

This is when running npx jest --debug

Codeium at 2:55 pm, May 1, 2024

The error suggests that Jest is having trouble parsing the TypeScript syntax. This can occur if Jest is not properly configured to handle TypeScript or if the necessary transformations are not set up.

To resolve this, ensure that ts-jest is correctly configured because ts-jest is responsible for transforming TypeScript files into JavaScript that Jest can understand. Here are the steps to check and update your configuration:

Ensure that you have ts-jest installed:
```
npm install --save-dev ts-jest
```

Verify your Jest configuration in jest.config.ts. It should include a preset for ts-jest:

import type { Config } from '@jest/types';

const config: Config.InitialOptions = {
  preset: 'ts-jest',
  testEnvironment: 'jsdom',
  // Your other configurations...
};

export default config;

If you have a Babel configuration file (.babelrc or babel.config.js), ensure that it's set up to work with TypeScript if you're using Babel alongside ts-jest.
Ensure that your TypeScript configuration file (tsconfig.json) is set up correctly and that it includes the necessary options for Jest. For example, you might have a separate TypeScript configuration for testing, such as tsconfig.jest.json, which you can reference in your Jest config:
```
globals: {
  'ts-jest': {
    tsconfig: 'tsconfig.jest.json'
  }
}
```
Clear Jest's cache to ensure that it's not using outdated transformations:
```
npx jest --clearCache
```
Run Jest with the --debug flag to get more information about the configuration it's using:
```
npx jest --debug
```

If you continue to have trouble, ensure that your TypeScript files have the correct .ts extension and that there are no syntactical errors in your code. Also, check that your tsconfig.json allows for esModuleInterop.

If the issue persists, please share the relevant parts of your jest.config.ts, tsconfig.json, and any other configuration files that could affect this setup, such as .babelrc or babel.config.js, if they exist.

User at 2:57 pm, May 1, 2024

I have these in my package.json

 "devDependencies": {
  "@types/jest": "^29.5.12",
  "concurrently": "^8.2.2",
  "jest": "^29.7.0",
  "jest-environment-jsdom": "^29.7.0",
  "ts-jest": "^29.1.2",
  "ts-node": "^10.9.2",
  "typescript": "^5.4.5"
 },

Codeium at 2:57 pm, May 1, 2024

Your package.json file shows that you have the necessary packages for testing with Jest and TypeScript. However, the issue might still be related to the Jest configuration or the TypeScript transpilation process.

Here's what you can check and try:

Verify jest.config.ts: Ensure it's using the ts-jest preset and has the jsdom environment set. Your jest.config.ts should look something like this:

import type { Config } from '@jest/types';

const config: Config.InitialOptions = {
  preset: 'ts-jest',
  testEnvironment: 'jest-environment-jsdom',
  // Other configurations...
};

export default config;

Check TypeScript Configuration: Make sure your tsconfig.json is compatible with Jest. If you have a separate TypeScript config for testing (like tsconfig.jest.json), ensure it's correctly referenced in jest.config.ts.
Run Jest with Clear Cache: Clear the Jest cache to ensure it uses the latest configurations.

npx jest --clearCache

Run Jest with Debug Information: Run Jest with the --debug flag to get detailed information about the configuration Jest is using.

npx jest --debug

Check for Syntax Errors: Ensure there are no syntax errors in your TypeScript test files. The error message you received earlier about a missing semicolon might actually be a red herring, and the actual issue could be a different syntax problem.
Check Babel Configuration (if applicable): If you're using Babel alongside ts-jest, ensure Babel is correctly configured to work with TypeScript.

If these steps do not resolve the issue, it might be helpful to see the actual content of your jest.config.ts and a snippet of the test file that's causing the problem to provide more specific guidance.

User at 3:03 pm, May 1, 2024

The jest.config.ts didn't have the preset

Now when I run it I get a long error that starts with this:

 FAIL static/js/terminal/XtermAdapter.test.js
 ● Console

  console.error
   Error: Not implemented: HTMLCanvasElement.prototype.getContext (without installing the canvas npm package)
     at module.exports (D:\T3\Projects\self\handex.io\node_modules\jsdom\lib\jsdom\browser\not-implemented.js:9:17)   
     at HTMLCanvasElementImpl.getContext (D:\T3\Projects\self\handex.io\node_modules\jsdom\lib\jsdom\living\nodes\HTMLCanvasElement-impl.js:42:5)
     at HTMLCanvasElement.getContext (D:\T3\Projects\self\handex.io\node_modules\jsdom\lib\jsdom\living\generated\HTMLCanvasElement.js:131:58)

Codeium at 3:03 pm, May 1, 2024

The error message you're seeing indicates that the test is trying to use the getContext method of the HTMLCanvasElement, which is not implemented in jsdom by default. The jsdom environment provided by Jest is a lightweight simulation of the browser's environment and does not implement the full functionality of browser APIs, including the canvas API.

To fix this issue, you have two options:

Mock the Canvas Method: In your test setup, you can mock the getContext method of HTMLCanvasElement to prevent this error. This is useful if you don't need to test the actual canvas drawing logic.

Here's an example of how you might mock the getContext method:

beforeAll(() => {
  // Mock the getContext method of the HTMLCanvasElement
  HTMLCanvasElement.prototype.getContext = () => {
    // Return a mock canvas context object
    return {
      // Implement the necessary methods and properties you need for your tests
    };
  };
});

Install the canvas Package: If you need a more complete implementation of the canvas API for your tests, you can install the canvas package provided by npm. This package allows you to use canvas in a Node.js environment.

Install the canvas package by running:
```
npm install canvas
```
Once installed, jsdom will be able to use it when the getContext method is called.

Choose the option that best suits your testing needs. If you only need to ensure that the method is called with the correct parameters, mocking will suffice. However, if you need to perform actual canvas operations, you should install the canvas package.

User at 3:09 pm, May 1, 2024

I installed canvas because I will be doing more elaborate things with the HTML output.

Now I am getting this error:

 FAIL static/js/terminal/XtermAdapter.test.js
 ● XtermAdapter › should add command element to commandHistory when user enters a command

  TypeError: this._parentWindow.matchMedia is not a function

   19 |   // this._terminalElement.appendChild(this.createPromptElement());
   20 |   this.terminal = new Terminal();
  > 21 |   this.terminal.open(element);
     |          ^
   22 |   this.terminal.onData(this.onDataHandler.bind(this));
   23 |   this.loadCommandHistory();
   24 |  }

   at a._resolutionMediaMatchList [as _updateDpr] (node_modules/@xterm/xterm/lib/webpack:/@xterm/xterm/src/browser/services/CoreBrowserService.ts:126:10)

Codeium at 3:09 pm, May 1, 2024

The error message is indicating that within the @xterm/xterm library, there's a call to matchMedia on a _parentWindow object, which is not available in the jsdom environment used by Jest.

While jsdom does provide a lot of the browser APIs, it doesn't implement everything. The matchMedia method is used to check the media query of the document in a browser environment which is typically used for responsive design purposes.

To resolve this issue, you can mock the matchMedia method in your test setup. Add the following code at the top of your test file or in a setup file that runs before your tests:

Object.defineProperty(window, 'matchMedia', {
  writable: true,
  value: jest.fn().mockImplementation(query => ({
    matches: false,
    media: query,
    onchange: null,
    addListener: jest.fn(), // Deprecated
    removeListener: jest.fn(), // Deprecated
    addEventListener: jest.fn(),
    removeEventListener: jest.fn(),
    dispatchEvent: jest.fn(),
  })),
});

This will create a mock function for matchMedia that returns an object with the necessary properties and methods to avoid throwing errors when called by the @xterm/xterm library.

After adding this mock, run your tests again to see if the issue is resolved. If you encounter more functions or methods that are not implemented in jsdom, you may need to continue mocking them similarly until your tests run without errors.

User at 3:13 pm, May 1, 2024

I added that to the top of the test file but I am still getting this:

 FAIL static/js/terminal/XtermAdapter.test.js
 ● XtermAdapter › should add command element to commandHistory when user enters a command
                                                               
  TypeError: this._parentWindow.matchMedia is not a function                                
                                                               
   19 |   // this._terminalElement.appendChild(this.createPromptElement());                       
   20 |   this.terminal = new Terminal();                                        
  > 21 |   this.terminal.open(element);                                         
     |          ^                                                
   22 |   this.terminal.onData(this.onDataHandler.bind(this));
   23 |   this.loadCommandHistory();
   24 |  }

   at a._resolutionMediaMatchList [as _updateDpr] (node_modules/@xterm/xterm/lib/webpack:/@xterm/xterm/src/browser/services/CoreBrowserService.ts:126:10)

Codeium at 3:13 pm, May 1, 2024

The issue persists because the matchMedia function is being accessed on a _parentWindow property within the @xterm/xterm library, rather than on the global window object. Since your test file is likely running in a Node environment via Jest, the global window object may not be available or may not be the same window that @xterm/xterm is trying to access.

To address this, you can try to specifically mock matchMedia on the window object that @xterm/xterm uses. However, this might be challenging without knowing the exact implementation details of the library.

As an alternative, you could try setting up a global mock for matchMedia in Jest's setup file, which runs before each test suite. This way, you'd ensure that the mock is available globally before any modules are required. Here's how you can do it:

Create a Jest setup file (if you don't have one already) and add it to your Jest configuration:

Create a file named jest.setup.ts in your project.

Add the following code to jest.setup.ts:

Object.defineProperty(global, 'window', {
  value: {
    matchMedia: jest.fn().mockImplementation(query => ({
      matches: false,
      media: query,
      onchange: null,
      addListener: jest.fn(),
      removeListener: jest.fn(),
      addEventListener: jest.fn(),
      removeEventListener: jest.fn(),
      dispatchEvent: jest.fn(),
    })),
  },
});

Update your Jest configuration to use the setup file:

// jest.config.ts
import type { Config } from '@jest/types';

const config: Config.InitialOptions = {
  preset: 'ts-jest',
  testEnvironment: 'jest-environment-jsdom',
  setupFilesAfterEnv: ['<rootDir>/path/to/your/jest.setup.ts'],
  // ... other configurations
};

export default config;

Run Jest again after making these changes to see if the issue is resolved.

By setting up the mock in a global setup file, you ensure that the matchMedia mock is available before any test code is executed. If this still does not resolve the issue, it may be related to how @xterm/xterm is interacting with the mocked window object, and you might need to explore more detailed mocking strategies or consider contributing a fix to the library if it's not handling the Node environment correctly.

2024 05 01 troubleshooting typescript tests for terminal app - bizkite-co/handterm GitHub Wiki

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