[Offload] Skip most liboffload tests if no devices

[RossBrunton]

If there are no devices available for testing on liboffload, the test
will no longer throw an error when it fails to instantiate.

The tests will be silently skipped, but with a warning printed to
stderr.

[llvmbot]

@llvm/pr-subscribers-offload

Author: Ross Brunton (RossBrunton)

Changes

If there are no devices available for testing on liboffload, the test
will no longer throw an error when it fails to instantiate.

The tests will be silently skipped, but with a warning printed to
stderr.

---

Full diff: https://github.com/llvm/llvm-project/pull/157417.diff

2 Files Affected:

• (modified) offload/unittests/OffloadAPI/common/Environment.cpp (+3)
• (modified) offload/unittests/OffloadAPI/common/Fixtures.hpp (+5-1)

diff --git a/offload/unittests/OffloadAPI/common/Environment.cpp b/offload/unittests/OffloadAPI/common/Environment.cpp
index 80077138b8cc8..024094aec2e49 100644
--- a/offload/unittests/OffloadAPI/common/Environment.cpp
+++ b/offload/unittests/OffloadAPI/common/Environment.cpp
@@ -129,6 +129,9 @@ const std::vector<TestEnvironment::Device> &TestEnvironment::getDevices() {
     }
   }
 
+  if (Devices.size() <= 1)
+    errs() << "Warning: No devices found for OffloadAPI tests.\n";
+
   return Devices;
 }
 
diff --git a/offload/unittests/OffloadAPI/common/Fixtures.hpp b/offload/unittests/OffloadAPI/common/Fixtures.hpp
index 0538e60f276e3..c5a35faba7a27 100644
--- a/offload/unittests/OffloadAPI/common/Fixtures.hpp
+++ b/offload/unittests/OffloadAPI/common/Fixtures.hpp
@@ -250,9 +250,13 @@ struct OffloadEventTest : OffloadQueueTest {
   ol_event_handle_t Event = nullptr;
 };
 
+// Devices might not be available for offload testing, so allow uninstantiated
+// tests (as the device list will be empty). This means that all tests requiring
+// a device will be silently skipped.
 #define OFFLOAD_TESTS_INSTANTIATE_DEVICE_FIXTURE(FIXTURE)                      \
   INSTANTIATE_TEST_SUITE_P(                                                    \
       , FIXTURE, ::testing::ValuesIn(TestEnvironment::getDevices()),           \
       [](const ::testing::TestParamInfo<TestEnvironment::Device> &info) {      \
         return SanitizeString(info.param.Name);                                \
-      })
+      });                                                                      \
+  GTEST_ALLOW_UNINSTANTIATED_PARAMETERIZED_TEST(FIXTURE)

[mgorny]

Thanks for doing this. It's a bit verbose, but as long as the tests pass, I'm happy with it. Just one small comment.

[mgorny]

Yeah, still works for me, so I guess it's good for the GPU case as well.