PYTHON-4988: Check C extensions are loaded ONLY in CPython builds (#2016)

Author: Jibola

.evergreen/run-tests.sh

@@ -38,6 +38,7 @@ export PIP_PREFER_BINARY=1 # Prefer binary dists by default
 
 set +x
 python -c "import sys; sys.exit(sys.prefix == sys.base_prefix)" || (echo "Not inside a virtual env!"; exit 1)
+PYTHON_IMPL=$(python -c "import platform; print(platform.python_implementation())")
 
 # Try to source local Drivers Secrets
 if [ -f ./secrets-export.sh ]; then
@@ -48,7 +49,7 @@ else
 fi
 
 # Ensure C extensions have compiled.
-if [ -z "${NO_EXT:-}" ]; then
+if [ -z "${NO_EXT:-}" ] && [ "$PYTHON_IMPL" = "CPython" ]; then
     python tools/fail_if_no_c.py
 fi
 
@@ -245,7 +246,6 @@ python -c 'import sys; print(sys.version)'
 
 # Run the tests with coverage if requested and coverage is installed.
 # Only cover CPython. PyPy reports suspiciously low coverage.
-PYTHON_IMPL=$(python -c "import platform; print(platform.python_implementation())")
 if [ -n "$COVERAGE" ] && [ "$PYTHON_IMPL" = "CPython" ]; then
     # Keep in sync with combine-coverage.sh.
     # coverage >=5 is needed for relative_files=true.

.evergreen/utils.sh

@@ -78,6 +78,7 @@ testinstall () {
     PYTHON=$1
     RELEASE=$2
     NO_VIRTUALENV=$3
+    PYTHON_IMPL=$(python -c "import platform; print(platform.python_implementation())")
 
     if [ -z "$NO_VIRTUALENV" ]; then
         createvirtualenv $PYTHON venvtestinstall
@@ -86,7 +87,11 @@ testinstall () {
 
     $PYTHON -m pip install --upgrade $RELEASE
     cd tools
-    $PYTHON fail_if_no_c.py
+
+    if [ "$PYTHON_IMPL" = "CPython" ]; then
+        $PYTHON fail_if_no_c.py
+    fi
+
     $PYTHON -m pip uninstall -y pymongo
     cd ..