[SYCL] Add test plan for sycl_ext_oneapi_launch_queries extension

sycl/test-e2e/Experimental/launch_queries/test_plan.md

@@ -0,0 +1,87 @@
+# Test plan for [`sycl_ext_oneapi_launch_queries`][spec-link] extension
+
+## Testing scope
+
+### Device coverage
+
+The unit tests should be launched on every supported device configuration we
+have.
+
+### Type coverage
+
+Each query is templated on a single template type argument `Param`
+with some queries being template overloads of each other.
+Each query has a restriction on the value of `Param` defined
+in the relevant section of the spec. 
+
+Param must be one of the following types defined in 
+`sycl::ext::oneapi::experiemntal::info::kernel` namespace:
+- `max_work_item_sizes<1>`
+- `max_work_item_sizes<2>`
+- `max_work_item_sizes<3>`
+- `max_work_group_size`
+- `max_num_work_groups`
+- `max_sub_group_size`
+- `num_sub_groups`
+
+The tests should cover all of these types.
+
+## Tests
+
+### Unit tests
+
+#### Interface tests
+
+These tests are intended to check that all classes and methods defined by the
+extension have correct implementation, i.e.: right signatures, right return
+types, all necessary constraints are checked/enforced, etc.
+
+These tests should check the following:
+
+- that each query is not available when the template argument `Param` has
+  a value different than the one in the spec.
+- that each query can be called with the appropriate value for `Param` and the
+  appropriate argument types as defined by its signature.
+- the return types of all queries match the spec.
+
+Tests in this category may not perform some useful actions to exercise the
+extension functionality in full, but instead they are focused on making sure
+that all APIs are consistent with respect to other APIs.
+
+#### Consistency with device-specific queries
+
+Verify, for each query in the extension, that the value returned is smaller
+than or equal than the value returned when querying the corresponding
+device-specific queries.
+
+For example, 
+
+- `max_work_item_sizes<dim>` can be compared with 
+`sycl::info::device::max_work_item_sizes<dim>`
+- `max_work_group_size` can be compared with `sycl::info::device::max_work_group_size`
+- `max_num_work_groups` can be compared with `sycl::ext::oneapi::experimental::info::device::max_work_groups<dim>`
+- `max_sub_group_size` can be compared with `sycl::info::kernel_device_specific::max_sub_group_size`
+- `num_sub_groups` can be compared with `sycl::info::device::max_num_sub_groups`
+
+#### Consistency of `max_sub_group_size` queries
+
+The test needs to check that all three `ext_oneapi_get_info` queries for
+which `Param == max_sub_group_size` return the same value as
+`sub_group::get_max_local_range()` inside the kernel.
+
+#### Check behavior in the case of invalid arguments to queries
+
+For all queries for which `Param == max_num_work_groups` or
+`Param == max_sub_group_size` or `Param == num_sub_groups`, verify that
+a synchronous `exception` with the error code `errc::invalid` is thrown
+if the work-group size `r` is 0.
+
+#### Check return value of queries depending on queue submission status
+
+Verify that if kernel submission to a queue does not throw then
+the return value of each query on the queue with the given kernel 
+is strictly greater than 0.
+Likewise, verify that if at least one query returns 0, then kernel
+submission throws.
+
+[spec-link]: https://github.com/intel/llvm/blob/sycl/sycl/doc/extensions/proposed/sycl_ext_oneapi_launch_queries.asciidoc