Move non-conformance/adapter tests to lit (#17580)

This adds support for lit to unified-runtime, in the form
of a new target `check-unified-runtime`. This target is available
when UR is built standalone and when built as part of dpcpp.

In addition, there are targets like `check-unified-runtime-unit`
which run a subset of the lit tests.

When built standalone, `lit` and `filecheck` must be avilable in
the path. A `requirements_testing.txt` file is available to
install test dependencies.

When built as part of dpcpp, a new cmake variable is available;
`SYCL_UR_BUILD_TESTS` which is off by default. When enabled,
`check-unified-runtime` will be available as a target and will
also run as part of `check-all`.

All tests have been ported with the exception of:
* Adapter tests
* Conformance tests

The Python version for macos was also bumped to 3.10 to enable
use of a newer filecheck version.

Author: RossBrunton

README.md

@@ -148,15 +148,29 @@ List of options provided by CMake:
 | UR_HIP_HSA_INCLUDE_DIRS | Path of the ROCm HSA include directory | Directory path | `${UR_HIP_ROCM_DIR}/hsa/include;${UR_HIP_ROCM_DIR}/include` |
 | UR_HIP_LIB_DIR | Path of the ROCm HIP library directory | Directory path | `${UR_HIP_ROCM_DIR}/lib` |
 
-### Additional make targets
+### Testing
 
-To run tests, do the following:
+Unified Runtime uses `lit` and `FileCheck` as part of its test suite. When built as
+part of an LLVM build, the binaries provided by LLVM will be used. When built standalone,
+both `lit` and `FileCheck` (or `filecheck`) must be visible on `$PATH`. The easiest way
+to do this is to install the Python packages for `lit` and `filecheck`.
+
+```bash
+$ source .venv/bin/activate
+$ pip install -r third_party/requirements_testing.txt
+```
+
+> Note: `filecheck` requires Python >= 3.10; if you get errors claiming that `filecheck` is not available, update your Python version or disable testing.
+
+Once installed, tests can be executed using:
 
 ```bash
 $ make
 $ make test
 ```
 
+### Additional make targets
+
 To run automated code formatting, configure CMake with `UR_FORMAT_CPP_STYLE` option
 and then run a custom `cppformat` target:
 

cmake/FindLit.cmake

@@ -0,0 +1,29 @@
+# Copyright (C) 2025 Intel Corporation
+# Part of the Unified-Runtime Project, under the Apache License v2.0 with LLVM Exceptions.
+# See LICENSE.TXT
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+
+# There are two modes to finding lit and filecheck
+# If we are a standalone build, use the python packages
+# If we are not a standalone build, use the one provided by LLVM
+# Note that the python filecheck re-implementation isn't 100% compatible, but hopefully for simple tests it should be
+# good enough
+
+if(UR_STANDALONE_BUILD)
+  # Standalone build
+  find_program(URLIT_LIT_BINARY "lit")
+  if(NOT URLIT_LIT_BINARY)
+    message(FATAL_ERROR "No `lit` binary was found in path. Consider installing the python Package `lit`")
+  endif()
+
+  find_program(URLIT_FILECHECK_BINARY NAMES "filecheck" "FileCheck")
+  if(NOT URLIT_FILECHECK_BINARY)
+    message(FATAL_ERROR "No `filecheck` or `FileCheck` binary was found in path. Consider installing the python Package `filecheck`")
+  endif()
+else()
+  # In source build
+
+  # This will be in the $PATH
+  set(URLIT_FILECHECK_BINARY "FileCheck")
+endif()