chore: add sample function parameters, without type annotations (#1540)

* chore: add sample function parameters, without type annotations

Author: dizcology

packages/gapic-generator/gapic/configurable_snippetgen/configured_snippet.py

@@ -79,12 +79,21 @@ def filename(self) -> str:
         sync_or_async = "sync" if self.is_sync else "async"
         return f"{module_name}_{self.api_version}_generated_{service_name}_{snake_case_rpc_name}_{config_id}_{sync_or_async}.py"
 
+    def _add_sample_function_parameters(self) -> None:
+        # TODO: https://github.com/googleapis/gapic-generator-python/issues/1537, add typing annotation in sample function parameters.
+        params = []
+        for config_parameter in self.config.signature.parameters:
+            params.append(libcst_utils.convert_parameter(config_parameter))
+        parameters = libcst.Parameters(params=params)
+        self._sample_function_def = self._sample_function_def.with_changes(
+            params=parameters
+        )
+
     def _build_sample_function(self) -> None:
         # TODO: https://github.com/googleapis/gapic-generator-python/issues/1536, add return type.
-        # TODO: https://github.com/googleapis/gapic-generator-python/issues/1537, add sample function parameters.
         # TODO: https://github.com/googleapis/gapic-generator-python/issues/1538, add docstring.
         # TODO: https://github.com/googleapis/gapic-generator-python/issues/1539, add sample function body.
-        pass
+        self._add_sample_function_parameters()
 
     def _add_sample_function(self) -> None:
         self._module = self._module.with_changes(

packages/gapic-generator/gapic/configurable_snippetgen/libcst_utils.py

@@ -34,3 +34,26 @@ def base_function_def(function_name: str, is_sync: bool) -> libcst.FunctionDef:
     )
 
     return function_def
+
+
+def convert_expression(
+    config_expression: snippet_config_language_pb2.Expression,
+) -> libcst.BaseExpression:
+    value_name = config_expression.WhichOneof("value")
+    if value_name == "string_value":
+        string_value = config_expression.string_value
+        return libcst.SimpleString(value=f'"{string_value}"')
+    else:
+        raise ValueError(
+            f"Conversion from Expression value {value_name} unsupported.")
+
+
+def convert_parameter(
+    config_parameter: snippet_config_language_pb2.Statement.Declaration,
+) -> libcst.Param:
+    # TODO: https://github.com/googleapis/gapic-generator-python/issues/1537, add typing annotation in sample function parameters.
+    param = libcst.Param(
+        name=libcst.Name(value=config_parameter.name),
+        default=convert_expression(config_parameter.value),
+    )
+    return param

packages/gapic-generator/tests/unit/configurable_snippetgen/test_configured_snippet.py

@@ -104,7 +104,7 @@ def test_code(snippet):
     # https://github.com/googleapis/gapic-generator-python/issues/1522
     # Placeholder code.  We will gradually add to the ConfiguredSnippet class
     # until the generated code is the same as that of the golden file.
-    expected_code = """def sample_create_custom_class_Basic():
+    expected_code = """def sample_create_custom_class_Basic(parent = "projects/[PROJECT]/locations/us", custom_class_id = "passengerships"):
     \"\"
 """
     assert snippet.code == expected_code

packages/gapic-generator/tests/unit/configurable_snippetgen/test_libcst_utils.py

@@ -17,6 +17,7 @@
 import pytest
 
 from gapic.configurable_snippetgen import libcst_utils
+from gapic.configurable_snippetgen import snippet_config_language_pb2
 
 
 def _assert_code_equal(node: libcst.CSTNode, code: str) -> str:
@@ -41,3 +42,36 @@ def test_base_function_def(is_sync, expected_code):
 
     # Sometimes it is more convenient to just verify the code.
     _assert_code_equal(node, expected_code)
+
+
+def test_convert_expression_string_value():
+    config_expression = snippet_config_language_pb2.Expression(
+        string_value="hello world"
+    )
+    node = libcst_utils.convert_expression(config_expression)
+    expected_node = libcst.SimpleString(value='"hello world"')
+
+    assert node.deep_equals(expected_node), (node, expected_node)
+
+
+def test_convert_expression_should_raise_error_if_unsupported():
+    config_expression = snippet_config_language_pb2.Expression(
+        default_value=snippet_config_language_pb2.Expression.DefaultValue.DEFAULT_VALUE
+    )
+    with pytest.raises(ValueError):
+        libcst_utils.convert_expression(config_expression)
+
+
+def test_convert_parameter():
+    config_parameter = snippet_config_language_pb2.Statement.Declaration(
+        name="some_variable",
+        value=snippet_config_language_pb2.Expression(
+            string_value="hello world"),
+    )
+    node = libcst_utils.convert_parameter(config_parameter)
+    expected_node = libcst.Param(
+        name=libcst.Name(value="some_variable"),
+        default=libcst.SimpleString(value='"hello world"'),
+    )
+
+    assert node.deep_equals(expected_node), (node, expected_node)