Almost all test scripts currently need to override the __init__()
method. When they do that they need to call into super().__init__() as
the base class does some generic initialization.
This commit makes the base class __init__() call into set_test_params()
method. Individual test cases can override set_test_params() to setup
their test parameters.
Commit 9db8eecac1 improved the
assert_raises_jsonrpc() function for better testing of RPC failure
modes. This commit completes the job by removing remaining broken
try-except RPC testing from the individual test cases and replacing it
with calls to assert_raises_jsonrpc().
This commit fixes the module-level docstrings for the tests and helper
modules in qa. Many of these tests were uncommented previously - this
commit ensures that every test case has at least a minimum level of
commenting.