Bazel-ify most of the Python scripts. (#229)

proposals/scripts/BUILD

@@ -0,0 +1,35 @@
+# Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+# Exceptions. See /LICENSE for license information.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+load("@rules_python//python:defs.bzl", "py_binary", "py_library", "py_test")
+
+py_library(
+    name = "proposals",
+    srcs = ["proposals.py"],
+)
+
+py_test(
+    name = "proposals_test",
+    srcs = ["proposals_test.py"],
+    deps = [":proposals"],
+)
+
+py_binary(
+    name = "new_proposal",
+    srcs = ["new_proposal.py"],
+)
+
+py_test(
+    name = "new_proposal_test",
+    srcs = ["new_proposal_test.py"],
+    data = ["//proposals:template.md"],
+    deps = [":new_proposal"],
+)
+
+# This is a directly runnable script, but should not be run via bazel.
+py_library(
+    name = "update_proposal_list",
+    srcs = ["update_proposal_list.py"],
+    deps = [":proposals"],
+)

proposals/scripts/README.md

@@ -9,9 +9,3 @@ SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 Scripts for use with proposals.
 
 See individual scripts for more details.
-
-Please use `pytest` for testing:
-
-```
-$ pip install pytest
-```

proposals/scripts/new_proposal_test.py

@@ -12,7 +12,7 @@ import os
 import unittest
 from unittest import mock
 
-from proposals.scripts import new_proposal
+from carbon.proposals.scripts import new_proposal
 
 
 class FakeExitError(Exception):
@@ -61,7 +61,8 @@ class TestNewProposal(unittest.TestCase):
 
     def test_run_failure(self):
         with mock.patch(
-            "proposals.scripts.new_proposal._exit", side_effect=_fake_exit
+            "carbon.proposals.scripts.new_proposal._exit",
+            side_effect=_fake_exit,
         ):
             self.assertRaises(FakeExitError, new_proposal._run, ["false"])
 

proposals/scripts/proposals_test.py

@@ -8,7 +8,7 @@ SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
 import unittest
 
-from proposals.scripts import proposals
+from carbon.proposals.scripts import proposals
 
 
 class TestProposal(unittest.TestCase):

proposals/scripts/update_proposal_list.py

@@ -10,15 +10,19 @@ SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
 import io
 import os
+import importlib.util
 import re
 import sys
 
-# To support direct runs, ensure the pythonpath has the repo root.
-_PYTHONPATH = os.path.realpath(os.path.join(os.path.dirname(__file__), "../.."))
-if _PYTHONPATH not in sys.path:
-    sys.path.insert(0, _PYTHONPATH)
-
-from proposals.scripts import proposals
+# Do some extra work to support direct runs.
+try:
+    from carbon.proposals.scripts import proposals
+except ImportError:
+    proposals_spec = importlib.util.spec_from_file_location(
+        "proposals", os.path.join(os.path.dirname(__file__), "proposals.py")
+    )
+    proposals = importlib.util.module_from_spec(proposals_spec)
+    proposals_spec.loader.exec_module(proposals)
 
 if __name__ == "__main__":
     proposals_path = proposals.get_path()