Add Bazel Python library and test. (#882)

Usage:

```
py_binary(
    name = "py_example",
    srcs = ["py_example.py"],
    deps = ["@opencc//:py_opencc"]
)
```

.github/workflows/bazel.yml

@@ -16,5 +16,9 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - uses: bazelbuild/setup-bazelisk@v3
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
       - run: bazel build //:opencc
-      - run: bazel test --test_output=all //src/... //data/... //test/...
+      - run: bazel test --test_output=all //src/... //data/... //test/... //python/...

BUILD.bazel

@@ -1,3 +1,6 @@
+load("@rules_cc//cc:defs.bzl", "cc_library")
+load("@rules_python//python:py_library.bzl", "py_library")
+
 package(default_visibility = ["//visibility:public"])
 
 cc_library(
@@ -17,3 +20,10 @@ cc_library(
         "//src:opencc",
     ],
 )
+
+py_library(
+    name = "py_opencc",
+    deps = [
+        "//python/opencc",
+    ],
+)

MODULE.bazel

@@ -9,7 +9,22 @@ module(
 bazel_dep(name = "darts-clone", version = "0.32")
 bazel_dep(name = "googletest", version = "1.15.0", dev_dependency = True)
 bazel_dep(name = "marisa-trie", version = "0.2.6")
+bazel_dep(name = "platforms", version = "0.0.10")
+bazel_dep(name = "pybind11_bazel", version = "2.12.0")
 bazel_dep(name = "rapidjson", version = "1.1.0")
 bazel_dep(name = "rules_cc", version = "0.0.9")
 bazel_dep(name = "rules_python", version = "0.34.0")
 bazel_dep(name = "tclap", version = "1.2.5")
+
+
+python = use_extension("@rules_python//python/extensions:python.bzl", "python")
+python.toolchain(
+    python_version = "3.12",
+)
+pip = use_extension("@rules_python//python/extensions:pip.bzl", "pip")
+pip.parse(
+    hub_name = "pip",
+    python_version = "3.12",
+    requirements_lock = "//python/tests:requirements_lock.txt",
+)
+use_repo(pip, "pip")

python/opencc/BUILD.bazel

@@ -0,0 +1,15 @@
+load("@rules_python//python:py_library.bzl", "py_library")
+
+package(default_visibility = ["//visibility:public"])
+
+py_library(
+    name = "opencc",
+    srcs = ["__init__.py"],
+    data = [
+        "//data/config",
+        "//data/dictionary:binary_dictionaries",
+        "//data/dictionary:text_dictionaries",
+    ],
+    imports = [".."],
+    deps = ["//src:py_opencc"],
+)

python/opencc/__init__.py

@@ -3,13 +3,18 @@
 import os
 import sys
 
-from opencc.clib import opencc_clib
+try:
+    import opencc_clib               
+except ImportError:
+    from opencc.clib import opencc_clib
 
 __all__ = ['OpenCC', 'CONFIGS', '__version__']
 
 __version__ = opencc_clib.__version__
-_thisdir = os.path.dirname(os.path.abspath(__file__))
-_opencc_share_dir = os.path.join(_thisdir, 'clib', 'share', 'opencc')
+_this_dir = os.path.dirname(os.path.abspath(__file__))
+_opencc_share_dir = os.path.join(_this_dir, 'clib', 'share', 'opencc')
+_opencc_rootdir =  os.path.abspath(os.path.join(_this_dir, '..', '..'))
+_opencc_configdir = os.path.join(_opencc_rootdir, 'data', 'config')
 
 if sys.version_info.major == 2:
     text_type = unicode  # noqa
@@ -18,6 +23,8 @@
 
 if os.path.isdir(_opencc_share_dir):
     CONFIGS = [f for f in os.listdir(_opencc_share_dir) if f.endswith('.json')]
+elif os.path.isdir(_opencc_configdir):
+    CONFIGS = [f for f in os.listdir(_opencc_configdir) if f.endswith('.json')]
 else:
     CONFIGS = []
 
@@ -39,7 +46,9 @@ def __init__(self, config='t2s'):
         if not config.endswith('.json'):
             config += '.json'
         if not os.path.isfile(config):
-            config = os.path.join(_opencc_share_dir, config)
+            config_under_share_dir = os.path.join(_opencc_share_dir, config)
+            if os.path.isfile(config_under_share_dir):
+                config = config_under_share_dir
         super(OpenCC, self).__init__(config)
         self.config = config
 

python/tests/BUILD.bazel

@@ -0,0 +1,16 @@
+load("@pip//:requirements.bzl", "requirement")
+load("@rules_python//python:py_test.bzl", "py_test")
+
+py_test(
+    name = "test_opencc",
+    srcs = ["test_opencc.py"],
+    data = [
+        "//test/testcases",
+    ],
+    imports = [".."],
+    deps = [
+        "//python/opencc",
+        requirement("pytest"),
+        requirement("exceptiongroup"),
+    ],
+)

python/tests/requirements_lock.txt

@@ -0,0 +1,5 @@
+exceptiongroup==1.2.2
+iniconfig==2.0.0
+packaging==24.1
+pluggy==1.5.0
+pytest==8.3.2

python/tests/test_opencc.py

@@ -1,6 +1,9 @@
 from __future__ import unicode_literals
 
 import os
+import pytest
+import sys
+
 from glob import glob
 
 _this_dir = os.path.dirname(os.path.abspath(__file__))
@@ -39,3 +42,7 @@ def test_conversion():
         for text, ans in zip(intexts, anstexts):
             assert converter.convert(text) == ans, \
                 'Failed to convert {} for {} -> {}'.format(pref, text, ans)
+
+
+if __name__ == "__main__":
+    sys.exit(pytest.main(sys.argv[1:]))

src/BUILD.bazel

@@ -1,4 +1,6 @@
+load("@pybind11_bazel//:build_defs.bzl", "pybind_extension")
 load("@rules_cc//cc:defs.bzl", "cc_library")
+load("@rules_python//python:py_library.bzl", "py_library")
 
 package(default_visibility = ["//visibility:public"])
 
@@ -328,6 +330,18 @@ cc_library(
     ],
 )
 
+pybind_extension(
+    name = "opencc_clib",
+    srcs = ["py_opencc.cpp"],
+    deps = [":opencc"],
+)
+
+py_library(
+    name = "py_opencc",
+    data = [":opencc_clib"],
+    imports = ["."],
+)
+
 cc_library(
     name = "segmentation",
     srcs = ["Segmentation.cpp"],