HTTPS REDIRECTION : Specific NODE using iRULE

I wrote a simplified variant of your iRule. Tested and works as expected.

when HTTP_REQUEST {
    if { [HTTP::host] equals "www.myfancydomain.com" && [HTTP::uri] starts_with "/test" } {
        node 10.100.153.40 3000
    }
}

Note that I am matching the HTTP::host with equals, not with contains, because HTTP::host should be an exact match anyways.

Also I used HTTP::uri instead of HTTP::path and, but more important, I use starts_with, because HTTP::uri might also be /test/image1.jpg, test/index.html...

Differences between are explained here:

https://clouddocs.f5.com/api/irules/HTTP__path.html

https://clouddocs.f5.com/api/irules/HTTP__uri.html

Differences between contains, equals, starts_with and so on here:

https://devcentral.f5.com/s/articles/irules-101-02-if-and-expressions

And since you are always matching the same HTTP::host value, you might want to remove that check from your iRule logic and go for a switch statement to only match the HTTP::uri. Something like this.

switch -glob [HTTP::uri] {
  "/foo*" {
    # this will match on any string that starts with "/foo"
  }
  "*bar" {
    # this will match on any string that ends with "bar"
  }....

For details see here: https://devcentral.f5.com/s/articles/irules-101-04-switch