fix: Failed site creation resets the directory

[dcalhoun]

Related to #4 (comment).

Proposed Changes

• Reintroduce directory reset when site creation fails to simplify retrying.
• Refactor manual mocks to share foundational module mocks.
• Refactor fs mocks to support reading different files.
• Run main process tests in the Node.js environment for more realistic results
  and faster runs.

Testing Instructions

In addition to the following, exploratory/regression testing around site creation is welcome.

Failed site creation resets the directory

1. Checkout the proposed changes.
2. Apply the below intentional error diff.
3. npm start
4. Click "Add site" in the bottom-left corner.
5. Click "Add site" in the modal.
6. Verify a helpful error message is displayed.
7. Verify the failed site directory is moved to the OS trash.
8. Click the "local path" input and select the default Studio directory.
9. Click "Add site" in the modal.
10. Verify the site is successfully created and server started.

Intentional error diff

diff --git a/src/site-server.ts b/src/site-server.ts
index 4ac8ab3..563926b 100644
--- a/src/site-server.ts
+++ b/src/site-server.ts
@@ -16,6 +16,8 @@ import { getSiteThumbnailPath } from './storage/paths';
 
 const servers = new Map< string, SiteServer >();
 
+let forceFailure = true;
+
 export async function createSiteWorkingDirectory(
 	path: string,
 	wpVersion = 'latest'
@@ -28,6 +30,11 @@ export async function createSiteWorkingDirectory(
 	await purgeWpConfig( wpVersion );
 	await recursiveCopyDirectory( getWordPressVersionPath( wpVersion ), path );
 
+	if ( forceFailure ) {
+		forceFailure = false;
+		throw new Error( 'Simulated failure' );
+	}
+
 	return true;
 }
 

Pre-merge Checklist

• Have you checked for TypeScript, React or other console errors?

[dcalhoun]

Like other new files in src/__mocks__, these mocks were hoisted here to simplify sharing these foundational module mocks across various test files.

[dcalhoun]

Sourced from the Jest documentation, implemented to allow simultaneously mocking file contents from different locations.

[dcalhoun]

Using the node testing environment should provide a more realistic environment for main process tests. Also, the tests should run faster.

[dcalhoun]

If we want to mock Node's built-in modules (e.g.: fs or path), then explicitly calling e.g. jest.mock('path') is required, because built-in modules are not mocked by default.

– Jest Manual Mocks documentation

[kozer]

I tested it and worked as expected:

1. Originally I got the error
   
2. Verified the delete site
   
3. The second time the site created successfully.

Also note, that I run all tests to verify that everything work as expected

Nice work @dcalhoun !

[sejas]

Awesome!, The change looks great! 👍
Now users can re-try after a new site creation fails.
Thank you!

[sejas]

Nice!, thanks for introducing the logic!