feat[test]: add more transient storage tests (#3883)

this commit adds dedicated tests for basic operations in the transient
storage location. it mostly follows the dedicated tests for immutables
and copies them where relevant.

it also adds a `requires_evm_version` marker, which can be used in
future to test language features which should be blocked in certain EVM
versions.

---------

Co-authored-by: cyberthirst <cyberthirst.eth@gmail.com>

setup.cfg

@@ -31,4 +31,5 @@ testpaths = tests
 xfail_strict = true
 markers =
 	fuzzing: Run Hypothesis fuzz test suite (deselect with '-m "not fuzzing"')
+	requires_evm_version(version): Mark tests that require at least a specific EVM version and would throw `EvmVersionException` otherwise
 	venom_xfail: mark a test case as a regression (expected to fail) under the venom pipeline

tests/conftest.py

@@ -22,6 +22,8 @@
 from vyper.codegen.ir_node import IRnode
 from vyper.compiler.input_bundle import FilesystemInputBundle, InputBundle
 from vyper.compiler.settings import OptimizationLevel, Settings, _set_debug_mode
+from vyper.evm.opcodes import version_check
+from vyper.exceptions import EvmVersionException
 from vyper.ir import compile_ir, optimizer
 from vyper.utils import ERC5202_PREFIX
 
@@ -580,3 +582,14 @@ def fn(exception=TransactionFailed, exc_text=None):
             assert exc_text in str(excinfo.value), (exc_text, excinfo.value)
 
     return fn
+
+
+def pytest_runtest_call(item):
+    marker = item.get_closest_marker("requires_evm_version")
+    if marker:
+        assert len(marker.args) == 1
+        version = marker.args[0]
+        if not version_check(begin=version):
+            item.add_marker(
+                pytest.mark.xfail(reason="Wrong EVM version", raises=EvmVersionException)
+            )

tests/functional/codegen/features/decorators/test_pure.py

@@ -198,3 +198,17 @@ def foo() -> uint256:
     """
     with pytest.raises(FunctionDeclarationException):
         compile_code(code)
+
+
+@pytest.mark.requires_evm_version("cancun")
+def test_invalid_transient_access():
+    code = """
+x: transient(uint256)
+
+@external
+@pure
+def foo() -> uint256:
+    return self.x
+    """
+    with pytest.raises(StateAccessViolation):
+        compile_code(code)

tests/functional/codegen/features/decorators/test_view.py

@@ -1,3 +1,5 @@
+import pytest
+
 from vyper.exceptions import FunctionDeclarationException
 
 
@@ -15,6 +17,20 @@ def foo() -> int128:
     print("Passed constant function test")
 
 
+@pytest.mark.requires_evm_version("cancun")
+def test_transient_test(get_contract):
+    code = """
+x: transient(uint256)
+
+@external
+@view
+def foo() -> uint256:
+    return self.x
+    """
+    c = get_contract(code)
+    assert c.foo() == 0
+
+
 def test_invalid_constant_and_payable(
     get_contract_with_gas_estimation_for_constants, assert_compile_failed
 ):