[Backend Tester] Add flow-specific skipped tests, skip argmin/max on Core ML due to native crashes, float16/64 on Vulkan (#13992)

Argmin and argmax are crashing on Core ML. Native crashes are hard to
recover from. In the medium term, I'd like to look at using
pytest-xdist, which, by nature of process isolation, can recover. But
for now, I'm adding a way to skip tests on specific backend flows to
allow running the remaining tests. I've also skipped Vulkan float16 and
float64 tests, as they crash when using swiftshader (used in the CI for
software execution of the Vulkan compute shaders). This should be
re-visited in the future.

There is also a little technical debt in the code duplication between
operator and model tests. This will also be cleaned up shortly.

Author: GregoryComer

backends/test/suite/flow.py

@@ -1,6 +1,6 @@
 import logging
 
-from dataclasses import dataclass
+from dataclasses import dataclass, field
 from typing import Callable
 
 from executorch.backends.test.harness import Tester
@@ -35,6 +35,12 @@ class TestFlow:
     is_delegated: bool = True
     """ Indicates whether the flow is expected to generate CALL_DELEGATE nodes. """
 
+    skip_patterns: list[str] = field(default_factory=lambda: [])
+    """ Tests with names containing any substrings in this list are skipped. """
+
+    def should_skip_test(self, test_name: str) -> bool:
+        return any(pattern in test_name for pattern in self.skip_patterns)
+
 
 def all_flows() -> dict[str, TestFlow]:
     flows = []

backends/test/suite/flows/coreml.py

@@ -19,6 +19,7 @@ def _create_coreml_flow(
             CoreMLTester, minimum_deployment_target=minimum_deployment_target
         ),
         quantize=quantize,
+        skip_patterns=["test_argmin", "test_argmax"],
     )
 
 

backends/test/suite/flows/vulkan.py

@@ -20,6 +20,7 @@ def _create_vulkan_flow_base(
         tester_factory=VulkanTester,
         quantize=quantize_stage_factory is not None,
         quantize_stage_factory=quantize_stage_factory,
+        skip_patterns=["float16", "float64"],  # Not supported in swiftshader
     )
 
 

backends/test/suite/models/__init__.py

@@ -52,6 +52,11 @@ def wrapped_test(self):
             "use_dynamic_shapes": use_dynamic_shapes,
         }
         with TestContext(test_name, test_func.__name__, flow.name, params):
+            if flow.should_skip_test(test_name):
+                raise unittest.SkipTest(
+                    f"Skipping test due to matching flow {flow.name} skip patterns"
+                )
+
             test_func(self, flow, dtype, use_dynamic_shapes)
 
     wrapped_test._name = test_func.__name__  # type: ignore

backends/test/suite/operators/__init__.py

@@ -97,6 +97,11 @@ def _make_wrapped_test(
 ):
     def wrapped_test(self):
         with TestContext(test_name, test_base_name, flow.name, params):
+            if flow.should_skip_test(test_name):
+                raise unittest.SkipTest(
+                    f"Skipping test due to matching flow {flow.name} skip patterns"
+                )
+
             test_kwargs = copy.copy(params) or {}
             test_kwargs["flow"] = flow