feat: create docs README file

Author: ohmayr

.generator/cli.py

@@ -350,6 +350,14 @@ def _copy_files_needed_for_post_processing(output: str, input: str, library_id:
             f"{output}/{path_to_library}/.repo-metadata.json",
         )
 
+    source_readme_path = Path(output) / path_to_library / "README.rst"
+    if source_readme_path.exists():
+        destination_docs_dir = Path(output) / path_to_library / "docs"
+        destination_readme_path = destination_docs_dir / "README.rst"
+
+        os.makedirs(destination_docs_dir, exist_ok=True)
+        shutil.copy(source_readme_path, destination_readme_path)
+
     # copy post-procesing files
     for post_processing_file in glob.glob(
         f"{input}/client-post-processing/*.yaml"

.generator/test_cli.py

@@ -814,6 +814,28 @@ def test_copy_files_needed_for_post_processing_copies_metadata_if_exists(mocker)
     mock_makedirs.assert_called()
 
 
+def test_copy_files_needed_for_post_processing_copies_readme(mocker):
+    """Tests that README.rst is copied to the docs directory if it exists."""
+    mock_makedirs = mocker.patch("os.makedirs")
+    mock_shutil_copy = mocker.patch("shutil.copy")
+    mock_path_exists = mocker.patch("pathlib.Path.exists", return_value=True)
+    mocker.patch("os.path.exists", return_value=False)  # for .repo-metadata.json
+
+    _copy_files_needed_for_post_processing("output", "input", "google-cloud-language")
+
+    mock_makedirs.assert_called_with(
+        Path("output") / "packages" / "google-cloud-language" / "docs", exist_ok=True
+    )
+    mock_shutil_copy.assert_called_with(
+        Path("output") / "packages" / "google-cloud-language" / "README.rst",
+        Path("output")
+        / "packages"
+        / "google-cloud-language"
+        / "docs"
+        / "README.rst",
+    )
+
+
 def test_copy_files_needed_for_post_processing_skips_metadata_if_not_exists(mocker):
     """Tests that .repo-metadata.json is not copied if it does not exist."""
     mock_makedirs = mocker.patch("os.makedirs")