fetch solc binary, fixes CI

Author: felix314159

docs/writing_tests/tutorials/state_transition.md

@@ -18,7 +18,7 @@ The most effective method of learning how to write tests is to study a couple of
 
 ### Yul Test
 
-You can find the source code for the Yul test in [tests/homestead/yul/test_yul_example.py](../../tests/homestead/yul/test_yul_example/index.md).
+You can find the source code for the Yul test in `tests/homestead/yul/test_yul_example.py`.
 It is the spec test equivalent of this [static test](https://github.com/ethereum/tests/blob/develop/src/GeneralStateTestsFiller/stExample/yulExampleFiller.yml).
 
 Lets examine each section.

tox.ini

@@ -66,9 +66,27 @@ setenv =
     # Use custom EELS_RESOLUTIONS_FILE if it is set via the environment (eg, in CI)
     EELS_RESOLUTIONS_FILE = {env:EELS_RESOLUTIONS_FILE:}
     CI = {env:CI:}
+    # Add the solc binary directory to PATH
+    PATH = {envdir}/bin{:}{env:PATH}
 extras = 
     test
     lint # Required `gentest` for formatting tests
+allowlist_externals =
+    mkdir
+    curl
+    wget
+    chmod
+    test
+    solc
+commands_pre =
+    # Create bin directory
+    mkdir -p {envdir}/bin
+    # Download solc if it doesn't exist
+    test -f {envdir}/bin/solc || curl -L -o {envdir}/bin/solc https://github.com/ethereum/solidity/releases/download/v0.8.24/solc-static-linux
+    # Make it executable
+    chmod +x {envdir}/bin/solc
+    # Verify it works
+    solc --version
 commands =
     pytest -c ./pytest-framework.ini -n auto -m "not run_in_serial"
     pytest -c ./pytest-framework.ini -m run_in_serial