fix: The DB API Binary function accepts bytes data

google/cloud/bigquery/dbapi/types.py

@@ -30,16 +30,27 @@
 TimestampFromTicks = datetime.datetime.fromtimestamp
 
 
-def Binary(string):
+def Binary(data):
     """Contruct a DB-API binary value.
 
     Args:
-        string (str): A string to encode as a binary value.
+        data (bytes-like): An object containing binary data and that
+                           can be converted to bytes with the `bytes` builtin.
 
     Returns:
-        bytes: The UTF-8 encoded bytes representing the string.
+        bytes: The binary data as a bytes object.
     """
-    return string.encode("utf-8")
+    if isinstance(data, int):
+        # This is not the conversion we're looking for, because it
+        # will simply create a bytes object of the given size.
+        raise TypeError("cannot convert 'decimal.Decimal' object to binary")
+    try:
+        return bytes(data)
+    except TypeError:
+        if isinstance(data, str):
+            return data.encode("utf-8")
+        else:
+            raise
 
 
 def TimeFromTicks(ticks, tz=None):

tests/unit/test_dbapi_types.py

@@ -13,6 +13,7 @@
 #  limitations under the License.
 
 import datetime
+import pytest
 import unittest
 
 import google.cloud._helpers
@@ -29,6 +30,19 @@ def test_binary_type(self):
     def test_binary_constructor(self):
         self.assertEqual(types.Binary(u"hello"), b"hello")
         self.assertEqual(types.Binary(u"\u1f60"), u"\u1f60".encode("utf-8"))
+        self.assertEqual(types.Binary(b"hello"), b"hello")
+        self.assertEqual(types.Binary(bytearray(b"hello")), b"hello")
+        self.assertEqual(types.Binary(memoryview(b"hello")), b"hello")
+
+        class C:
+            def __bytes__(self):
+                return b"Google"
+
+        self.assertEqual(types.Binary(C()), b"Google")
+
+        for bad in 42, 42.0, None:
+            with pytest.raises(TypeError):
+                types.Binary(bad)
 
     def test_timefromticks(self):
         somedatetime = datetime.datetime(