Update Components build and E2E testing instructions (#56106)

Author: sebastienros

src/Components/README.md

@@ -29,42 +29,56 @@ The following contains a description of each sub-directory in the `Components` d
 
 ## Development Setup
 
-### Build
+**Note**: To build other specific projects from source, follow the instructions [on building the project](../../docs/BuildFromSource.md#step-3-build-the-repo).
 
-To build this specific project from source, follow the instructions [on building the project](../../docs/BuildFromSource.md#step-3-build-the-repo).
+### Building ASP.NET Core Components
 
-**Note:** You also need to run the preceding `build` command in the command line before building in VS to ensure that the Web.JS dependency is built.
+1. You'll need to install [Node](https://nodejs.org) on your machine.
 
-### A Guide to build Web.JS
+1. Ensure the repository is clean from any asset that could remain from previous version of the repository. This is recommended when switching branches, or after updating the working branch.
 
-Prior to building `src\Components\Web.JS\`
+```powershell
+git clean -xdff
+```
 
-1. You'll need to install [Node](https://nodejs.org) on your machine.
+You may need to kill some processes holding on files that are being deleted, like closing Visual Studio and other `msbuild` or `dotnet` processes. There may also be lingering headless `chrome` processes, but they are not included in this command. The following command may help you but be aware that this could also stop other important tasks:
+
+```powershell
+Get-Process dotnet, escape-node-job, msbuild, VBCSCompiler, node, vstest.console, Microsoft.CodeAnalysis.LanguageServer -ErrorAction Continue | Stop-Process;
+```
 
-2. You'll need to run the `restore` script locally to install the required dotnet dependencies and setup the repo. The `restore` script is located in the root of the repo.
+1. Use NPM to restore the required JavaScript modules. This doesn't require an Internet connection since the sources are read from a sub-module.
+
+```powershell
+npm ci --offline
+```
+
+1. You'll need to run the `restore` script locally to install the required dotnet dependencies and setup the repo. The `restore` script is located in the root of the repo.
 
 ```bash
 ./restore.sh
 ```
 
 ```powershell
-./restore.ps1
+./restore.cmd
 ```
 
-3. After the restore script has finished executing, activate the locally installed .NET by running the following command.
+1. Now you can build all the JavaScript assets required by the repository (including SignalR for instance) by running the following command:
 
-```bash
-source activate.sh
+```powershell
+npm run build
 ```
 
+1. Build the Components:
+
 ```powershell
-. ./activate.ps1
+./src/Components/build.cmd
 ```
 
-4. Now you can build `src\Components\Web.JS\` by running the following commands in the `src\Components\Web.JS` directory:
+2. Optionally, open the Components in Visual Studio:
 
 ```powershell
-dotnet build
+./src/Components/startvs.cmd
 ```
 
 ### Test
@@ -84,23 +98,22 @@ These tests are run in the CI as part of the [`aspnetcore-components-e2e`](https
 
 #### How to run the E2E Tests
 
-To run the tests for this project, follow these steps (from the root directory):
+The E2E tests can be run and debugged directly from Visual Studio (as explained in the previous section). To run the tests from the command line,
+follow the previous build steps and then these commands:
 
-##### Windows
+1. Activate the locally installed .NET by running the following command.
+
+```bash
+source activate.sh
+```
 
 ```powershell
-./restore.cmd
-npm install --prefix ./src/Components/test/E2ETest
-. .\activate.ps1
-dotnet test ./src/Components/test/E2ETest
+. ./activate.ps1
 ```
 
-##### Linux / MacOS
+1. Start the tests.
 
-```shell
-./restore.sh
-npm install --prefix ./src/Components/test/E2ETest
-source ./activate.sh
+```powershell
 dotnet test ./src/Components/test/E2ETest
 ```
 
@@ -123,4 +136,4 @@ dotnet test --no-build
 
 ## More Information
 
-For more information, see the [ASP.NET Core README](../../README.md).
+For more information, see the [ASP.NET Core README](https://github.com/dotnet/aspnetcore/blob/main/README.md).