[tests] Better GCC fixture enumeration.

examples/gcc_autotuning/tune_test.py

@@ -2,6 +2,7 @@
 #
 # This source code is licensed under the MIT license found in the
 # LICENSE file in the root directory of this source tree.
+import shutil
 import subprocess
 import sys
 from functools import lru_cache
@@ -24,33 +25,34 @@ def docker_is_available() -> bool:
         return False
 
 
-@lru_cache(maxsize=2)
-def system_gcc_is_available() -> bool:
+def system_has_functional_gcc(gcc_path: str) -> bool:
     """Return whether there is a system GCC available."""
     try:
         stdout = subprocess.check_output(
-            ["gcc", "--version"], universal_newlines=True, stderr=subprocess.DEVNULL
+            [gcc_path, "--version"],
+            universal_newlines=True,
+            stderr=subprocess.DEVNULL,
+            timeout=30,
         )
         # On some systems "gcc" may alias to a different compiler, so check for
         # the presence of the name "gcc" in the first line of output.
         return "gcc" in stdout.split("\n")[0].lower()
-    except (subprocess.CalledProcessError, FileNotFoundError):
+    except (
+        subprocess.CalledProcessError,
+        FileNotFoundError,
+        subprocess.TimeoutExpired,
+    ):
         return False
 
 
-def system_gcc_path() -> str:
-    """Return the path of the system GCC as a string."""
-    return subprocess.check_output(
-        ["which", "gcc"], universal_newlines=True, stderr=subprocess.DEVNULL
-    ).strip()
-
-
+@lru_cache
 def gcc_bins() -> Iterable[str]:
     """Return a list of available GCCs."""
     if docker_is_available():
         yield "docker:gcc:11.2.0"
-    if system_gcc_is_available():
-        yield system_gcc_path()
+    system_gcc = shutil.which("gcc")
+    if system_gcc and system_has_functional_gcc(system_gcc):
+        yield system_gcc
 
 
 @pytest.fixture(scope="module", params=gcc_bins())

tests/pytest_plugins/gcc.py

@@ -4,6 +4,7 @@
 # LICENSE file in the root directory of this source tree.
 """Pytest fixtures for the GCC CompilerGym environments."""
 
+import shutil
 import subprocess
 from functools import lru_cache
 from typing import Iterable
@@ -13,38 +14,44 @@
 from tests.pytest_plugins.common import docker_is_available
 
 
-@lru_cache(maxsize=2)
-def system_gcc_is_available() -> bool:
+def system_has_functional_gcc(gcc_path: str) -> bool:
     """Return whether there is a system GCC available."""
     try:
         stdout = subprocess.check_output(
-            ["gcc", "--version"], universal_newlines=True, stderr=subprocess.DEVNULL
+            [gcc_path, "--version"],
+            universal_newlines=True,
+            stderr=subprocess.DEVNULL,
+            timeout=30,
         )
         # On some systems "gcc" may alias to a different compiler, so check for
         # the presence of the name "gcc" in the first line of output.
         return "gcc" in stdout.split("\n")[0].lower()
-    except (subprocess.CalledProcessError, FileNotFoundError):
+    except (
+        subprocess.CalledProcessError,
+        FileNotFoundError,
+        subprocess.TimeoutExpired,
+    ):
         return False
 
 
-def system_gcc_path() -> str:
-    """Return the path of the system GCC as a string."""
-    return subprocess.check_output(
-        ["which", "gcc"], universal_newlines=True, stderr=subprocess.DEVNULL
-    ).strip()
-
-
-def gcc_environment_is_supported() -> bool:
-    """Return whether the requirements for the GCC environment are met."""
-    return docker_is_available() or system_gcc_is_available()
+@lru_cache
+def system_gcc_is_available():
+    return system_has_functional_gcc(shutil.which("gcc"))
 
 
+@lru_cache
 def gcc_bins() -> Iterable[str]:
     """Return a list of available GCCs."""
     if docker_is_available():
         yield "docker:gcc:11.2.0"
-    if system_gcc_is_available():
-        yield system_gcc_path()
+    system_gcc = shutil.which("gcc")
+    if system_gcc and system_has_functional_gcc(system_gcc):
+        yield system_gcc
+
+
+def gcc_environment_is_supported() -> bool:
+    """Return whether the requirements for the GCC environment are met."""
+    return len(list(gcc_bins())) > 0
 
 
 @pytest.fixture(scope="module", params=gcc_bins())