Add a bazel test that verifies that the jaxlib wheel builds.

jaxlib/tools/BUILD.bazel

@@ -46,6 +46,15 @@ py_binary(
     ],
 )
 
+py_test(
+    name = "build_wheel_test",
+    srcs = ["build_wheel_test.py"],
+    data = [":build_wheel"],
+    deps = [
+      "@bazel_tools//tools/python/runfiles",
+    ],
+)
+
 py_binary(
     name = "build_gpu_plugin_wheel",
     srcs = ["build_gpu_plugin_wheel.py"],

jaxlib/tools/build_wheel.py

@@ -76,7 +76,10 @@ pyext = "pyd" if build_utils.is_windows() else "so"
 
 
 def exists(src_file):
-  return r.Rlocation(src_file) is not None
+  path = r.Rlocation(src_file)
+  if path is None:
+    return False
+  return os.path.exists(path)
 
 
 def patch_copy_mlir_import(src_file, dst_dir):

jaxlib/tools/build_wheel_test.py

@@ -0,0 +1,32 @@
+# Copyright 2024 The JAX Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# This test verifies that the build_wheel.py runs successfully.
+
+import platform
+import subprocess
+import sys
+import tempfile
+
+from bazel_tools.tools.python.runfiles import runfiles
+
+r = runfiles.Create()
+
+with tempfile.TemporaryDirectory(prefix="jax_build_wheel_test") as tmpdir:
+  subprocess.run([
+    sys.executable, r.Rlocation("__main__/jaxlib/tools/build_wheel.py"),
+    f"--cpu={platform.machine()}",
+    f"--output_path={tmpdir}",
+    "--jaxlib_git_hash=12345678"
+  ], check=True)