Handle typing collisions and add validation to a files module for overlaping declarations (#582)

* Fix 'typing' import collisions.

* Fix formatting.

* Fix self-test issues.

* Validation for modules, different typing configurations

* add readme

* make warning

* fix format

---------

Co-authored-by: Scott Hendricks <scott.hendricks@confluent.io>

tests/test_typing_compiler.py

@@ -0,0 +1,80 @@
+import pytest
+
+from betterproto.plugin.typing_compiler import (
+    DirectImportTypingCompiler,
+    NoTyping310TypingCompiler,
+    TypingImportTypingCompiler,
+)
+
+
+def test_direct_import_typing_compiler():
+    compiler = DirectImportTypingCompiler()
+    assert compiler.imports() == {}
+    assert compiler.optional("str") == "Optional[str]"
+    assert compiler.imports() == {"typing": {"Optional"}}
+    assert compiler.list("str") == "List[str]"
+    assert compiler.imports() == {"typing": {"Optional", "List"}}
+    assert compiler.dict("str", "int") == "Dict[str, int]"
+    assert compiler.imports() == {"typing": {"Optional", "List", "Dict"}}
+    assert compiler.union("str", "int") == "Union[str, int]"
+    assert compiler.imports() == {"typing": {"Optional", "List", "Dict", "Union"}}
+    assert compiler.iterable("str") == "Iterable[str]"
+    assert compiler.imports() == {
+        "typing": {"Optional", "List", "Dict", "Union", "Iterable"}
+    }
+    assert compiler.async_iterable("str") == "AsyncIterable[str]"
+    assert compiler.imports() == {
+        "typing": {"Optional", "List", "Dict", "Union", "Iterable", "AsyncIterable"}
+    }
+    assert compiler.async_iterator("str") == "AsyncIterator[str]"
+    assert compiler.imports() == {
+        "typing": {
+            "Optional",
+            "List",
+            "Dict",
+            "Union",
+            "Iterable",
+            "AsyncIterable",
+            "AsyncIterator",
+        }
+    }
+
+
+def test_typing_import_typing_compiler():
+    compiler = TypingImportTypingCompiler()
+    assert compiler.imports() == {}
+    assert compiler.optional("str") == "typing.Optional[str]"
+    assert compiler.imports() == {"typing": None}
+    assert compiler.list("str") == "typing.List[str]"
+    assert compiler.imports() == {"typing": None}
+    assert compiler.dict("str", "int") == "typing.Dict[str, int]"
+    assert compiler.imports() == {"typing": None}
+    assert compiler.union("str", "int") == "typing.Union[str, int]"
+    assert compiler.imports() == {"typing": None}
+    assert compiler.iterable("str") == "typing.Iterable[str]"
+    assert compiler.imports() == {"typing": None}
+    assert compiler.async_iterable("str") == "typing.AsyncIterable[str]"
+    assert compiler.imports() == {"typing": None}
+    assert compiler.async_iterator("str") == "typing.AsyncIterator[str]"
+    assert compiler.imports() == {"typing": None}
+
+
+def test_no_typing_311_typing_compiler():
+    compiler = NoTyping310TypingCompiler()
+    assert compiler.imports() == {}
+    assert compiler.optional("str") == "str | None"
+    assert compiler.imports() == {}
+    assert compiler.list("str") == "list[str]"
+    assert compiler.imports() == {}
+    assert compiler.dict("str", "int") == "dict[str, int]"
+    assert compiler.imports() == {}
+    assert compiler.union("str", "int") == "str | int"
+    assert compiler.imports() == {}
+    assert compiler.iterable("str") == "Iterable[str]"
+    assert compiler.imports() == {"typing": {"Iterable"}}
+    assert compiler.async_iterable("str") == "AsyncIterable[str]"
+    assert compiler.imports() == {"typing": {"Iterable", "AsyncIterable"}}
+    assert compiler.async_iterator("str") == "AsyncIterator[str]"
+    assert compiler.imports() == {
+        "typing": {"Iterable", "AsyncIterable", "AsyncIterator"}
+    }