chore: speed up the labware stackup tests somewhat

The labware stackup integration tests rule but were also very slow,
because they were running serially and there are 8,000 of them. By
making them run in parallel using
concurrent.futures.ProcessPoolExecutor, we can make it take like a
minute instead of 2 hours.

Author: sfoster1

api/.gitignore

@@ -4,3 +4,4 @@ build
 htmlcov
 
 src/opentrons/_version.py
+tests/**/*.temp

api/tests/opentrons/protocol_engine/state/test_stackup_testing/in_subprocess_test.py

@@ -0,0 +1,68 @@
+"""Import to a subprocess to run the stackup test."""
+
+from typing import Any, cast
+
+from opentrons import protocol_api, simulate
+from .stackup_spec import StackupSpec
+
+
+def run_test_subprocess(  # noqa: C901
+    spec: StackupSpec,
+) -> tuple[float, float, float]:
+    """Run the stackup test in a subprocess."""
+    context = simulate.get_protocol_api(
+        protocol_api.MAX_SUPPORTED_VERSION, robot_type=spec.robot_type
+    )
+
+    top_so_far: Any = None
+    module_load_name = spec.module_load_name
+    adapter_load_info = spec.adapter_load_info
+    labware_load_info = spec.labware_load_info
+
+    if module_load_name:
+        if module_load_name == "thermocyclerModuleV2":
+            module = context.load_module(module_load_name)
+        else:
+            module = context.load_module(module_load_name, "D3")
+            if module_load_name == "absorbanceReaderV1":
+                cast(protocol_api.AbsorbanceReaderContext, module).open_lid()
+        top_so_far = module
+
+    if adapter_load_info is not None:
+        adapter_load_name, adapter_version = adapter_load_info
+        if top_so_far is None:
+            adapter = context.load_adapter(
+                adapter_load_name, "D3", version=adapter_version
+            )
+        else:
+            if module_load_name == "absorbanceReaderV1":
+                adapter = context.load_labware(
+                    adapter_load_name, "A3", version=adapter_version
+                )
+                context.move_labware(adapter, module, use_gripper=True)
+            else:
+                adapter = top_so_far.load_adapter(
+                    adapter_load_name, version=adapter_version
+                )
+        top_so_far = adapter
+
+    labware_load_name, labware_version = labware_load_info
+    if top_so_far is None:
+        labware = context.load_labware(labware_load_name, "D3", version=labware_version)
+    else:
+        if module_load_name == "absorbanceReaderV1":
+            labware = context.load_labware(
+                labware_load_name, "A3", version=labware_version
+            )
+            if adapter_load_info is not None:
+                context.move_labware(labware, adapter, use_gripper=True)
+            else:
+                context.move_labware(labware, module, use_gripper=True)
+        else:
+            labware = top_so_far.load_labware(
+                labware_load_name, version=labware_version
+            )
+    top_so_far = labware
+
+    x, y, z = top_so_far.wells_by_name()["A1"].top().point
+    return (x, y, z)

api/tests/opentrons/protocol_engine/state/test_stackup_testing/stackup_spec.py

@@ -0,0 +1,30 @@
+"""Stackup spec."""
+
+from dataclasses import dataclass
+from typing import Any, Literal
+
+
+@dataclass(frozen=True)
+class StackupSpec:
+    """The test parameters of interest."""
+
+    robot_type: Literal["OT-2"] | Literal["Flex"]
+    module_load_name: str | None
+    adapter_load_info: tuple[str, int] | None
+    labware_load_info: tuple[str, int]
+
+    def to_dict(self) -> dict[str, Any]:
+        """Convert to dictionary for JSON serialization."""
+        return {
+            "robot_type": self.robot_type,
+            "module_load_name": self.module_load_name,
+            "adapter_load_info": self.adapter_load_info,
+            "labware_load_info": self.labware_load_info,
+        }
+
+    def stackup_key(self) -> str:
+        """Generate a unique key for this stackup configuration."""
+        module_name = self.module_load_name or "None"
+        adapter_name = self.adapter_load_info[0] if self.adapter_load_info else "None"
+        labware_name = self.labware_load_info[0]
+        return f"{self.robot_type},{module_name},{adapter_name},{labware_name}"