filter does not work in UnitTestTree

[cheng93]

Command

generate

Is this a regression?

• [ ] Yes, this behavior used to work in the previous version

The previous version in which this bug was not present was

No response

Description

filter() does not work when applied to a UnitTestTree

I believe this is because UnitTestTree is not a HostTree

Minimal Reproduction

https://github.com/cheng93/angular-schematics-filter

run the test in the hello-world schematics

Exception or Error

Error: Tree type is not supported.

Your Environment

_                      _                 ____ _     ___
    / \   _ __   __ _ _   _| | __ _ _ __     / ___| |   |_ _|
   / △ \ | '_ \ / _` | | | | |/ _` | '__|   | |   | |    | |
  / ___ \| | | | (_| | |_| | | (_| | |      | |___| |___ | |
 /_/   \_\_| |_|\__, |\__,_|_|\__,_|_|       \____|_____|___|
                |___/
    

Angular CLI: 16.1.8
Node: 20.0.0 (Unsupported)
Package Manager: npm 9.6.4
OS: win32 x64

Angular: 16.2.8
... animations, common, compiler, compiler-cli, core, forms
... platform-browser, platform-browser-dynamic, router

Package                      Version
------------------------------------------------------
@angular-devkit/architect    0.1601.8
@angular-devkit/core         16.1.8
@angular-devkit/schematics   16.1.8
@angular/cli                 16.1.8
@schematics/angular          16.1.8
rxjs                         7.8.1
typescript                   5.1.6
zone.js                      0.13.3

Anything else relevant?

No response