Add forced-decisions APIs to OptimizelyUserContext

[Mat001]

Summary

Add a set of new APIs for forced-decisions to OptimizelyUserContext:

• set_forced_decision
• get_forced_decision
• remove_forced_decision
• remove_all_forced_decisions

Test plan

• unit tests still to be written
• all FSC tests are passing, here: https://app.travis-ci.com/github/optimizely/fullstack-sdk-compatibility-suite/builds/242311652

Issues

• OASIS-7951: https://optimizely.atlassian.net/browse/OASIS-7951

[jaeopt]

Some early comments :)

[coveralls]

Coverage decreased (-0.3%) to 95.829% when pulling 201548f on mpirnovar/forced_decisions into a1e31eb on master.

[msohailhussain]

rest of the comments, @mnoman09 will verify.

[msohailhussain]

few more comments.

[mnoman09]

Suggested some changes.

[Mat001]

@msohailhussain @mnoman09 I consolidated the functions into one. Here:

python-sdk/optimizely/project_config.py

Lines 668 to 700 in ab40d9e

	def get_flag_variation(self, flag_key, variation_attribute, target_value):
	"""
	Gets variation by specified variation attribute.
	For example if variation_attribute is id, the function gets variation by using variation_id.
	If object_attribute is key, the function gets variation by using variation_key.
	We used to have two separate functions:
	get_flag_variation_by_id()
	get_flag_variation_by_key()
	This function consolidates both functions into one.
	Important to always relate object_attribute to the target value.
	Should never enter for example object_attribute=key and target_value=variation_id.
	Correct is object_attribute=key and target_value=variation_key.
	Args:
	flag_key: flag key
	variation_attribute: id or key for example. The part after the dot notation (id in variation.id)
	target_value: target value we want to get for example variation_id or variation_key
	Returns:
	Variation as a map.
	"""
	if not flag_key:
	return None
	variations = self.flag_variations_map.get(flag_key)
	for variation in variations:
	if getattr(variation, variation_attribute) == target_value:
	return variation
	return None

When you review this pls look carefully. The two functions I consolidated were each called on a different object:

get_flag_variation_by_id() was called on project_config. ----> in user_event_factory.py
get_flag_variation_by_key() was called on self.client. --------> inside find_validated_forced_decision()

So I made a little change in find_validated_forced_decision() here, so the single function is only called on project_config: https://github.com/optimizely/python-sdk/pull/361/files#diff-4df94492754236d1784d8b2987b84acd6af0ea3d97a0a2e54e61fb3f03acb04cR265-R268

unit tests and FSC tests pass.

[jaeopt]

A few changes suggested

[jaeopt]

All look good except for a small change suggested!

[The-inside-man]

LGTM!

[Mat001]

@msohailhussain @mnoman09 @yasirfolio3 Can you please approve this PR so I can merge it? (mark requested changes as resolved) TY

[jaeopt]

LGTM

already approved by 2 devx members.

[msohailhussain]

lgtm on behalf of yasir and noman.