What do you mean by "constructor injection"?

In .NET a lot of DI is done by adding another interface to the constructor. So if you need some service way down the stack you add it to the constructor. This then in turn can require adding this dependency to all the tests that use this service.

Comments like these really amaze me. What sort of competent editor cannot handle such simple refactorings?

My comment describes a way to organize unit tests to work around this issue.

Maybe but in Blazor you have the choice of Property or Constructor DI. This choice is in all the major DI container libraries I've worked with in .NET, around a dozen over the years.