fix(engine): allow dropping tips in any labware

[sanni-t]

Closes RSS-277

Overview

Fixes a bug introduced in 6.3.0 that unintentionally raises an error when trying to drop tips into labware that is neither a fixed trash nor a tiprack.

Our API documentation clearly states that you can specify an arbitrary tip drop location in instrument_context.drop_tip(). Furthermore, the API allows assigning any labware as the designated trash container for a particular pipette, which is treated as the default tip drop location.
For executing both these cases, the engine needs to allow dropping tips into any labware; not just tiprack or fixed trash.

This is also necessary for the upcoming 'post-run-tip-drop' flow that the app is planning on adding.

Test Plan

This protocol should drop tips into the fixed trash, the tip rack and a reservoir as expected
(Can also be tested on the OT-2 by updating the protocol for OT-2)

requirements = {
	"robotType": "Flex",
	"apiLevel": "2.15"
}

def run(protocol_context):
	# For Flex:
	tiprack1 = protocol_context.load_labware("opentrons_flex_96_tiprack_50ul", "D2")
	pipette = protocol_context.load_instrument("flex_1channel_50", 'left', tip_racks=[tiprack1])
	
	pipette.pick_up_tip()
	pipette.drop_tip()		# Should drop tip at TOP of fixed trash in A3 (at an alternating location)

        pipette.pick_up_tip()
	pipette.drop_tip()		# Should drop tip at TOP of fixed trash in A3 (at an alternating location)

	pipette.drop_tip(pipette.trash_container['A1'].center())	# Should always drop tip in CENTER of Fixed trash

	trash_labware = protocol_context.load_labware("nest_1_reservoir_195ml", "D1")
	pipette.trash_container = trash_labware

	pipette.pick_up_tip()
	pipette.drop_tip()		# Should drop tip at CENTER TOP of Nest reservoir (NO alternating locations)

	pipette.pick_up_tip()
	pipette.drop_tip(pipette.trash_container['A1'].center())	# Should always drop tip in CENTER of Nest reservoir

	pipette.pick_up_tip()
	pipette.return_tip()	        # Should return tip to tiprack

Changelog

• changed get_checked_tip_drop_location() to check if labware is tiprack, else drop tip to TOP of specified labware.
• updated tests

Review requests

• Make sure I am not messing up any side effects of tip dropping by allowing any arbitrary locations

Risk assessment

Low. Bug fix.

[codecov]

Codecov Report

Merging #13504 (64604d4) into chore_release-7.0.0 (dfa0892) will not change coverage.
Report is 25 commits behind head on chore_release-7.0.0.
The diff coverage is n/a.

Additional details and impacted files

@@                 Coverage Diff                  @@
##           chore_release-7.0.0   #13504   +/-   ##
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  Coverage                71.33%   71.33%           
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  Files                     2418     2418           
  Lines                    67908    67908           
  Branches                  7876     7876           
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  Hits                     48443    48443           
  Misses                   17623    17623           
  Partials                  1842     1842           

Flag	Coverage Δ
g-code-testing	96.44% <ø> (ø)
notify-server	89.13% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files Changed	Coverage Δ
...i/src/opentrons/protocol_api/instrument_context.py	88.95% <ø> (ø)
...pi/src/opentrons/protocol_engine/state/geometry.py	100.00% <ø> (ø)

[sanni-t]

Tested on an OT-2 with above protocol.

[SyntaxColoring]

Grazie!

[sanni-t]

Tested protocol successfully on Flex as well.