Following the paradigms illustrated in "Working Effectively with Legacy
Code", this commit introduces at least one test for each service class
implementation. This test is a simple construction test -- we just
create each service and assert that it exists. Each test suite includes
a comment instructing the developer who comes next to remove the
constructor test. We don't want to keep these tests as the codebase
matures, as they aren't useful in the longterm. They only prove that we
have that class under test.
Where test suites failed to construct their associated classes, we skip
the test but leave behind the implementation. This is by design, so that
as the constructors for those classes change, we are forced to keep the
test suite current by leaning on the compiler.
