youknowone · Nov 9, 2026 · Nov 8, 2026
diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
@@ -79,6 +79,9 @@ jobs:
             ':benches/**' \
             ':example_projects/**' \
             ':extra_tests/snippets/**' \
+            ':extra_tests/test_snippets.py' \
+            ':extra_tests/rustpython_wasi.sh' \
+            ':extra_tests/requirements.txt' \
             ':.github/workflows/ci.yaml' \
           ; then
               echo "changed=false" >> "$GITHUB_OUTPUT"
@@ -1055,7 +1058,6 @@ jobs:
         builtin_memoryview
         builtin_open
         builtin_posixshmem
-        builtin_slice
         builtin_str
         builtin_thread
         cli_int_max_str_digits
@@ -1179,19 +1181,23 @@ jobs:
       - name: build rustpython
         if: env.RUN_WASM_WASI == 'true'
         run: cargo build --locked --profile wasm-release --target wasm32-wasip1 --no-default-features --features freeze-stdlib,stdlib,stdio,importlib,host_env,doc,ucd_3_2_0 --verbose
+      - name: Setup Python for the snippet harness
+        if: env.RUN_WASM_WASI == 'true'
+        uses: actions/setup-python@5fda3b95a4ea91299a34e894583c3862153e4b97 # v7.0.0
+        with:
+          python-version-file: .python-version
+
+      - name: Install snippet harness dependencies
+        if: env.RUN_WASM_WASI == 'true'
+        run: python -m pip install -r extra_tests/requirements.txt
+
       - name: run snippets
         if: env.RUN_WASM_WASI == 'true'
-        run: |
-          exclude=" $WASM_WASI_SNIPPET_EXCLUDE "
-          for path in extra_tests/snippets/*.py; do
-            name=$(basename "$path" .py)
-            case "$exclude" in
-              *" $name "*) continue ;;
-            esac
-            echo "::group::${path}"
-            wasmer run --volume "$(pwd)" target/wasm32-wasip1/wasm-release/rustpython.wasm -- "$(pwd)/${path}"
-            echo "::endgroup::"
-          done
+        working-directory: extra_tests
+        env:
+          RUSTPYTHON: ${{ github.workspace }}/extra_tests/rustpython_wasi.sh
+          RUSTPYTHON_SNIPPET_EXCLUDE: ${{ env.WASM_WASI_SNIPPET_EXCLUDE }}
+        run: pytest -v test_snippets.py -k test_rustpython_
       - name: run cpython unittest
         if: env.RUN_WASM_WASI == 'true'
         run: |

diff --git a/extra_tests/rustpython_wasi.sh b/extra_tests/rustpython_wasi.sh
@@ -0,0 +1,7 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+repo_root=$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")/.." && pwd)
+exec wasmer run --volume "$repo_root" \
+  --env "RUSTPYTHONPATH=$repo_root/Lib" \
+  "$repo_root/target/wasm32-wasip1/wasm-release/rustpython.wasm" -- "$@"
diff --git a/extra_tests/test_snippet_selection.py b/extra_tests/test_snippet_selection.py
@@ -0,0 +1,33 @@
+import unittest
+from unittest.mock import patch
+
+import test_snippets
+
+
+class SnippetSelectionTests(unittest.TestCase):
+    def make_test(self, method, name):
+        class Tests:
+            pass
+
+        test_snippets.create_test_function(Tests, f"snippets/{name}.py", method, None)
+        return getattr(Tests, f"test_{method}_{name}")
+
+    def test_exclusion_matches_the_whole_snippet_name(self):
+        with patch.object(test_snippets, "RUSTPYTHON_SNIPPET_EXCLUDE", {"builtin_str"}):
+            excluded = self.make_test("rustpython", "builtin_str")
+            sibling = self.make_test("rustpython", "builtin_str_add")
+
+        self.assertTrue(excluded.__unittest_skip__)
+        self.assertFalse(getattr(sibling, "__unittest_skip__", False))
+
+    def test_exclusion_does_not_change_cpython_reference_tests(self):
+        with patch.object(test_snippets, "RUSTPYTHON_SNIPPET_EXCLUDE", {"builtin_str"}):
+            reference = self.make_test("cpython", "builtin_str")
+
+        self.assertFalse(getattr(reference, "__unittest_skip__", False))
+
+    def test_no_exclusions_keeps_the_native_default(self):
+        with patch.object(test_snippets, "RUSTPYTHON_SNIPPET_EXCLUDE", set()):
+            test = self.make_test("rustpython", "builtin_str")
+
+        self.assertFalse(getattr(test, "__unittest_skip__", False))
diff --git a/extra_tests/test_snippets.py b/extra_tests/test_snippets.py
@@ -51,6 +51,9 @@ def run_via_cpython(filename):
     ROOT_DIR, "target/release/rustpython"
 )
 RUSTPYTHON_BINARY = os.path.abspath(RUSTPYTHON_BINARY)
+RUSTPYTHON_SNIPPET_EXCLUDE = set(
+    os.environ.get("RUSTPYTHON_SNIPPET_EXCLUDE", "").split()
+)
 
 
 def run_via_rustpython(filename, test_type):
@@ -71,6 +74,14 @@ def create_test_function(cls, filename, method, test_type):
     def test_function(self):
         perform_test(filename, method, test_type)
 
+    if (
+        method == "rustpython"
+        and os.path.splitext(snippet_filename)[0] in RUSTPYTHON_SNIPPET_EXCLUDE
+    ):
+        test_function = unittest.skip("excluded by RUSTPYTHON_SNIPPET_EXCLUDE")(
+            test_function
+        )
+
     if hasattr(cls, test_function_name):
         raise ValueError("Duplicate test case {}".format(test_function_name))
     setattr(cls, test_function_name, test_function)