Remove unused code in Markdown sample (GoogleCloudPlatform#5396)

* Update sample

* Update tests

Author: averikitsch

run/markdown-preview/editor/main.py

@@ -35,11 +35,15 @@ def index():
 def render_handler():
     body = request.get_json()
     if not body:
-        raise Exception("Invalid JSON")
+        return "Error rendering markdown: Invalid JSON", 400
 
     data = body["data"]
-    parsed_markdown = render.new_request(data)
-    return parsed_markdown
+    try:
+        parsed_markdown = render.new_request(data)
+        return parsed_markdown, 200
+    except Exception as err:
+        return f"Error rendering markdown: {err}", 500
+
 # [END run_secure_request_do]
 # [END cloudrun_secure_request_do]
 

run/markdown-preview/editor/main_test.py

@@ -40,15 +40,15 @@ def test_render_handler_errors(client):
     r = client.get("/render")
     assert r.status_code == 405
 
-    with pytest.raises(Exception) as e:
-        client.post("/render", data="**markdown**")
-    assert "Invalid JSON" in str(e.value)
+    r = client.post("/render", data="**markdown**")
+    assert r.status_code == 400
+    assert "Invalid JSON" in r.data.decode()
 
 
 def test_missing_upstream_url(client):
     del os.environ["EDITOR_UPSTREAM_RENDER_URL"]
-    with pytest.raises(Exception) as e:
-        client.post("/render",
+    r = client.post("/render",
                     data=json.dumps({"data": "**strong text**"}),
                     headers={"Content-Type": "application/json"})
-    assert "EDITOR_UPSTREAM_RENDER_URL missing" in str(e.value)
+    assert r.status_code == 500
+    assert "EDITOR_UPSTREAM_RENDER_URL missing" in r.data.decode()

run/markdown-preview/editor/render.py

@@ -33,8 +33,6 @@ def new_request(data):
         raise Exception("EDITOR_UPSTREAM_RENDER_URL missing")
 
     req = urllib.request.Request(url, data=data.encode())
-
-    credentials, project = google.auth.default()
     auth_req = google.auth.transport.requests.Request()
     target_audience = url