tools: tc-testing: Introduce plugin architecture

This should be a general test architecture, and yet allow specific
tests to be done.  Introduce a plugin architecture.

An individual test has 4 stages, setup/execute/verify/teardown.  Each
plugin gets a chance to run a function at each stage, plus one call
before all the tests are called ("pre" suite) and one after all the
tests are called ("post" suite).  In addition, just before each
command is executed, the plugin gets a chance to modify the command
using the "adjust_command" hook.  This makes the test suite quite
flexible.

Future patches will take some functionality out of the tdc.py script and
place it in plugins.

To use the plugins, place the implementation in the plugins directory
and run tdc.py.  It will notice the plugins and use them.
Signed-off-by: Brenda J. Butler <bjb@mojatatu.com>
Acked-by: Lucas Bates <lucasb@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/testing/selftests/tc-testing/TdcPlugin.py

+#!/usr/bin/env python3
+
+class TdcPlugin:
+    def __init__(self):
+        super().__init__()
+        print(' -- {}.__init__'.format(self.sub_class))
+
+    def pre_suite(self, testcount, testidlist):
+        '''run commands before test_runner goes into a test loop'''
+        self.testcount = testcount
+        self.testidlist = testidlist
+        if self.args.verbose > 1:
+            print(' -- {}.pre_suite'.format(self.sub_class))
+
+    def post_suite(self, index):
+        '''run commands after test_runner completes the test loop
+        index is the last ordinal number of test that was attempted'''
+        if self.args.verbose > 1:
+            print(' -- {}.post_suite'.format(self.sub_class))
+
+    def pre_case(self, test_ordinal, testid):
+        '''run commands before test_runner does one test'''
+        if self.args.verbose > 1:
+            print(' -- {}.pre_case'.format(self.sub_class))
+        self.args.testid = testid
+        self.args.test_ordinal = test_ordinal
+
+    def post_case(self):
+        '''run commands after test_runner does one test'''
+        if self.args.verbose > 1:
+            print(' -- {}.post_case'.format(self.sub_class))
+
+    def pre_execute(self):
+        '''run command before test-runner does the execute step'''
+        if self.args.verbose > 1:
+            print(' -- {}.pre_execute'.format(self.sub_class))
+
+    def post_execute(self):
+        '''run command after test-runner does the execute step'''
+        if self.args.verbose > 1:
+            print(' -- {}.post_execute'.format(self.sub_class))
+
+    def adjust_command(self, stage, command):
+        '''adjust the command'''
+        if self.args.verbose > 1:
+            print(' -- {}.adjust_command {}'.format(self.sub_class, stage))
+
+        # if stage == 'pre':
+        #     pass
+        # elif stage == 'setup':
+        #     pass
+        # elif stage == 'execute':
+        #     pass
+        # elif stage == 'verify':
+        #     pass
+        # elif stage == 'teardown':
+        #     pass
+        # elif stage == 'post':
+        #     pass
+        # else:
+        #     pass
+
+        return command
+
+    def add_args(self, parser):
+        '''Get the plugin args from the command line'''
+        self.argparser = parser
+        return self.argparser
+
+    def check_args(self, args, remaining):
+        '''Check that the args are set correctly'''
+        self.args = args
+        if self.args.verbose > 1:
+            print(' -- {}.check_args'.format(self.sub_class))

tools/testing/selftests/tc-testing/creating-plugins/AddingPlugins.txt

+tdc - Adding plugins for tdc
+
+Author: Brenda J. Butler - bjb@mojatatu.com
+
+ADDING PLUGINS
+--------------
+
+A new plugin should be written in python as a class that inherits from TdcPlugin.
+There are some examples in plugin-lib.
+
+The plugin can be used to add functionality to the test framework,
+such as:
+
+- adding commands to be run before and/or after the test suite
+- adding commands to be run before and/or after the test cases
+- adding commands to be run before and/or after the execute phase of the test cases
+- ability to alter the command to be run in any phase:
+    pre        (the pre-suite stage)
+    prepare
+    execute
+    verify
+    teardown
+    post       (the post-suite stage)
+- ability to add to the command line args, and use them at run time
+
+
+The functions in the class should follow the following interfaces:
+
+    def __init__(self)
+    def pre_suite(self, testcount, testidlist)     # see "PRE_SUITE" below
+    def post_suite(self, ordinal)                  # see "SKIPPING" below
+    def pre_case(self, test_ordinal, testid)       # see "PRE_CASE" below
+    def post_case(self)
+    def pre_execute(self)
+    def post_execute(self)
+    def adjust_command(self, stage, command)       # see "ADJUST" below
+    def add_args(self, parser)                     # see "ADD_ARGS" below
+    def check_args(self, args, remaining)          # see "CHECK_ARGS" below
+
+
+PRE_SUITE
+
+This method takes a testcount (number of tests to be run) and
+testidlist (array of test ids for tests that will be run).  This is
+useful for various things, including when an exception occurs and the
+rest of the tests must be skipped.  The info is stored in the object,
+and the post_suite method can refer to it when dumping the "skipped"
+TAP output.  The tdc.py script will do that for the test suite as
+defined in the test case, but if the plugin is being used to run extra
+tests on each test (eg, check for memory leaks on associated
+co-processes) then that other tap output can be generated in the
+post-suite method using this info passed in to the pre_suite method.
+
+
+SKIPPING
+
+The post_suite method will receive the ordinal number of the last
+test to be attempted.  It can use this info when outputting
+the TAP output for the extra test cases.
+
+
+PRE_CASE
+
+The pre_case method will receive the ordinal number of the test
+and the test id.  Useful for outputing the extra test results.
+
+
+ADJUST
+
+The adjust_command method receives a string representing
+the execution stage and a string which is the actual command to be
+executed.  The plugin can adjust the command, based on the stage of
+execution.
+
+The stages are represented by the following strings:
+
+    'pre'
+    'setup'
+    'command'
+    'verify'
+    'teardown'
+    'post'
+
+The adjust_command method must return the adjusted command so tdc
+can use it.
+
+
+ADD_ARGS
+
+The add_args method receives the argparser object and can add
+arguments to it.  Care should be taken that the new arguments do not
+conflict with any from tdc.py or from other plugins that will be used
+concurrently.
+
+The add_args method should return the argparser object.
+
+
+CHECK_ARGS
+
+The check_args method is so that the plugin can do validation on
+the args, if needed.  If there is a problem, and Exception should
+be raised, with a string that explains the problem.
+
+eg:  raise Exception('plugin xxx, arg -y is wrong, fix it')

tools/testing/selftests/tc-testing/plugin-lib/README-PLUGINS

+tdc.py will look for plugins in a directory plugins off the cwd.
+Make a set of numbered symbolic links from there to the actual plugins.
+Eg:
+
+tdc.py
+plugin-lib/
+plugins/
+    __init__.py
+    10-rootPlugin.py -> ../plugin-lib/rootPlugin.py
+    20-valgrindPlugin.py -> ../plugin-lib/valgrindPlugin.py
+    30-nsPlugin.py -> ../plugin-lib/nsPlugin.py
+
+
+tdc.py will find them and use them.
+
+
+rootPlugin
+    Check if the uid is root.  If not, bail out.
+
+valgrindPlugin
+    Run the command under test with valgrind, and produce an extra set of TAP results for the memory tests.
+    This plugin will write files to the cwd, called vgnd-xxx.log.  These will contain
+    the valgrind output for test xxx.  Any file matching the glob 'vgnd-*.log' will be
+    deleted at the end of the run.
+
+nsPlugin
+    Run all the commands in a network namespace.