[rest] use azure json encoder for json input bodies (Azure#20361)

sdk/core/azure-core/CHANGELOG.md

@@ -4,6 +4,8 @@
 
 ### Features Added
 
+- We now use `azure.core.serialization.AzureJSONEncoder` to serialize `json` input to `azure.core.rest.HttpRequest`.
+
 ### Breaking Changes in the Provisional `azure.core.rest` package
 
 - The `text` property on `azure.core.rest.HttpResponse` and `azure.core.rest.AsyncHttpResponse` has changed to a method, which also takes

sdk/core/azure-core/azure/core/rest/_helpers.py

@@ -50,6 +50,7 @@
     from urlparse import urlparse  # type: ignore
 except ImportError:
     from urllib.parse import urlparse
+from azure.core.serialization import AzureJSONEncoder
 
 ################################### TYPES SECTION #########################
 
@@ -182,7 +183,7 @@ def set_content_body(content):
 
 def set_json_body(json):
     # type: (Any) -> Tuple[Dict[str, str], Any]
-    body = dumps(json)
+    body = dumps(json, cls=AzureJSONEncoder)
     return {
         "Content-Type": "application/json",
         "Content-Length": str(len(body))

sdk/core/azure-core/tests/testserver_tests/test_rest_http_request.py

@@ -277,6 +277,14 @@ def test_complicated_json(client):
     r = client.send_request(request)
     r.raise_for_status()
 
+def test_use_custom_json_encoder():
+    # this is to test we're using azure.core.serialization.AzureJSONEncoder
+    # to serialize our JSON objects
+    # since json can't serialize bytes by default but AzureJSONEncoder can,
+    # we pass in bytes and check that they are serialized
+    request = HttpRequest("GET", "/headers", json=bytearray("mybytes", "utf-8"))
+    assert request.content == '"bXlieXRlcw=="'
+
 # NOTE: For files, we don't allow list of tuples yet, just dict. Will uncomment when we add this capability
 # def test_multipart_multiple_files_single_input_content():
 #     files = [