To prevent integration tests from impacting the actual database, an in-memory database is often used. It simulates database behavior but operates entirely in memory, making tests faster and isolated. It's a common practice in ASP.NET Core testing.

One of the major advantages of ASP.NET Core is its ability to run on multiple platforms, including Windows, Linux, and macOS. This cross-platform compatibility provides greater flexibility in choosing the hosting environment for your ASP.NET Core applications.

When configuring ASP.NET Core Identity, the 'IdentityOptions' class is used to specify various settings, including policies like password strength and lockout duration. This class allows fine-grained control over the behavior of Identity.

The UseDefaultFiles middleware is used to serve default files, like index.html, when a user accesses the root URL of a web application. This middleware ensures that the SPA's default page is served correctly. Make sure to include app.UseDefaultFiles(); in your Configure method.

To enforce password reset every 90 days in ASP.NET Core Identity, you should configure the password expiration policy in the IdentityOptions during application startup. This policy can be set to require users to change their passwords after a specified number of days.

CI stands for Continuous Integration. It's a development practice where code changes are automatically built, tested, and integrated into the shared codebase frequently. This helps detect and fix integration issues early in the development process.

In this scenario, you would leverage SignalR, which is a real-time communication library for ASP.NET Core. SignalR allows for bi-directional communication between the client and server, making it ideal for scenarios where you need real-time updates without the overhead of constant polling.

In ASP.NET Core Identity, the SignInAsync method is used to authenticate a user with provided credentials. This method handles the process of validating the user's username and password against the stored user data in the Identity system. It creates a security token for the authenticated user, allowing them access to protected resources.

To define an optional section in a Razor layout, you would use the @RenderSection method. This method allows you to specify content that can be overridden by views that use the layout. It's a powerful feature for creating flexible layouts in ASP.NET Core.

When working on a machine without internet access, you can use the NuGet CLI to install NuGet packages from a local feed or folder. The NuGet CLI provides command-line tools for interacting with NuGet packages, making it a suitable choice for such scenarios.