Use explicit default arguments

Replicates graphql/graphql-js@468dfb5

Author: Cito

src/graphql/language/source.py

@@ -1,5 +1,3 @@
-from typing import Optional
-
 from .location import SourceLocation
 
 __all__ = ["Source"]
@@ -13,8 +11,8 @@ class Source:
     def __init__(
         self,
         body: str,
-        name: Optional[str] = None,
-        location_offset: Optional[SourceLocation] = None,
+        name: str = "GraphQL request",
+        location_offset: SourceLocation = SourceLocation(1, 1),
     ) -> None:
         """Initialize source input.
 
@@ -26,13 +24,13 @@ def __init__(
 
         line and column in location_offset are 1-indexed
         """
-
+        if not isinstance(body, str):
+            raise TypeError("body must be a string.")
         self.body = body
-        self.name = "GraphQL request" if name is None else name
-        if not location_offset:
-            location_offset = SourceLocation(1, 1)
-        elif not isinstance(location_offset, SourceLocation):
-            # noinspection PyProtectedMember,PyTypeChecker
+        if not isinstance(name, str):
+            raise TypeError("name must be a string.")
+        self.name = name
+        if not isinstance(location_offset, SourceLocation):
             location_offset = SourceLocation._make(location_offset)
         if location_offset.line <= 0:
             raise ValueError(

tests/language/test_source.py

@@ -1,9 +1,46 @@
 from pytest import raises  # type: ignore
 
-from graphql.language import Source
+from graphql.language import Source, SourceLocation
+from graphql.pyutils import dedent
 
 
 def describe_source():
+    def accepts_body_and_name():
+        source = Source("foo", "bar")
+        assert source.body == "foo"
+        assert source.name == "bar"
+
+    def accepts_location_offset():
+        location_offset = SourceLocation(2, 3)
+        source = Source("", "", location_offset)
+        assert source.location_offset is location_offset
+
+    def accepts_tuple_as_location_offset():
+        # noinspection PyTypeChecker
+        source = Source("", "", (2, 3))  # type: ignore
+        assert isinstance(source.location_offset, SourceLocation)
+        assert source.location_offset == (2, 3)
+
+    def uses_default_arguments():
+        source = Source("")
+        assert source.name == "GraphQL request"
+        assert isinstance(source.location_offset, SourceLocation)
+        assert source.location_offset == (1, 1)
+
+    def can_get_location():
+        body = dedent(
+            """
+            line 1
+            line 2
+            line 3
+            """
+        )
+        source = Source(body)
+        assert source.body == body
+        location = source.get_location(body.find("2"))
+        assert isinstance(location, SourceLocation)
+        assert location == (2, 6)
+
     def can_be_stringified():
         source = Source("")
         assert str(source) == "<Source name='GraphQL request'>"
@@ -26,10 +63,33 @@ def can_be_compared():
         assert not source == "bar"
         assert source != "bar"
 
+    def rejects_invalid_body_and_name():
+        with raises(TypeError, match="body must be a string\\."):
+            # noinspection PyTypeChecker
+            Source(None)  # type: ignore
+        with raises(TypeError, match="body must be a string\\."):
+            # noinspection PyTypeChecker
+            Source(1)  # type: ignore
+        with raises(TypeError, match="name must be a string\\."):
+            # noinspection PyTypeChecker
+            Source("", None)  # type: ignore
+        with raises(TypeError, match="name must be a string\\."):
+            # noinspection PyTypeChecker
+            Source("", 1)  # type: ignore
+
     def rejects_invalid_location_offset():
         def create_source(location_offset):
             return Source("", "", location_offset)
 
+        with raises(TypeError):
+            create_source(None)
+        with raises(TypeError):
+            create_source(1)
+        with raises(TypeError):
+            create_source((1,))
+        with raises(TypeError):
+            create_source((1, 2, 3))
+
         with raises(
             ValueError,
             match="line in location_offset is 1-indexed and must be positive\\.",