E2E tests require Python 3.7

[AlexeySachkov]

There is an inconsistency about minimum required python version: we have an implicit requirement for 3.7, whilst our explicit requirement is only 3.6

Explicit requirement is documented here:

llvm/llvm/CMakeLists.txt

Lines 839 to 842 in e753fae

	if(LLVM_INCLUDE_TESTS)
	# Lit test suite requires at least python 3.6
	set(LLVM_MINIMUM_PYTHON_VERSION 3.6)
	else()

Implicit requirement is caused by the following lines:

llvm/sycl/test-e2e/lit.cfg.py

Lines 380 to 381 in e753fae

	sp = subprocess.run((cmd), env=llvm_config.config.environment,
	shell=True, capture_output=True, text=True)

capture_output argument of subprocess.run does not exists in Python 3,6 and it is only added in Python 3.7:

Changed in version 3.7: Added the text parameter, as a more understandable alias of universal_newlines. Added the capture_output parameter.

stackoverflow suggests that we could use check_output function instead.

Alternatively, we could have raised our minimum required Python version to 3.7, but I don't think that it is a good idea, unless upstream LLVM does so.

@aelovikov-intel: FYI

[AlexeySachkov]

#16211 made me realize that our requirements have changed since then and 3.8 is a minimum required version now:

llvm/llvm/CMakeLists.txt

Lines 979 to 982 in 9b9e5de

	if(LLVM_INCLUDE_TESTS)
	# All LLVM Python files should be compatible down to this minimum version.
	set(LLVM_MINIMUM_PYTHON_VERSION 3.8)
	else()

Therefore, this is not an issue anymore