Hosting service unit tests are now able to better catch calls and

compare them to expected results in a way that provides better

information when those expectations don't match up.
We now spy on all relevant hosting service client methods through the

hosting service's client class, rather than a mix of the client instance

and the top-level HostingServiceClient class. This limits the scope of

our spies in cases where the service defines its own client class, but

also allow us to catch calls that may come from a different instance of

the client (such as when a backend instantiates it through a view that

we're accessing through the Django HTTP test client).
When asserting results of the HTTP calls, we no longer rely on just the

results of the http_request() method. We instead check the URL,

method, and POST/PUT body against what comes back from

build_http_request(). This allows us to more thoroughly test in the

event that this data gets modified by part of the HTTP machinery on the

client.
If any of the expectations during the assertion fail, a better error

message and stack trace will now be provided, helping to debug the

source of the problem. Previously, the data had to be printed and

scrutinized, making it harder to see how things broke.

All hosting service unit tests pass.