Maybe this'll do it

test/xandra_test.exs

@@ -1,6 +1,8 @@
 defmodule XandraTest do
   use ExUnit.Case, async: true
 
+  import XandraTest.IntegrationCase, only: [default_start_options: 0]
+
   doctest Xandra
 
   describe "options validation in Xandra.start_link/1" do
@@ -46,12 +48,12 @@ defmodule XandraTest do
   end
 
   test "supports DBConnection.status/1 without raising" do
-    conn = start_supervised!(Xandra)
+    conn = start_supervised!({Xandra, default_start_options()})
     assert DBConnection.status(conn) == :idle
   end
 
   test "raises for unsupported DBConnection callbacks" do
-    conn = start_supervised!(Xandra)
+    conn = start_supervised!({Xandra, default_start_options()})
 
     assert_raise ArgumentError, "Cassandra doesn't support transactions", fn ->
       assert DBConnection.transaction(conn, fn _ -> :ok end)
@@ -60,12 +62,16 @@ defmodule XandraTest do
 
   @tag :capture_log
   test "rescues DBConnection errors" do
-    conn =
-      start_supervised!(
-        {Xandra,
-         nodes: ["nonexistent-domain"], queue_target: 10, queue_interval: 10, pool_size: 0}
+    options =
+      Keyword.merge(default_start_options(),
+        nodes: ["nonexistent-domain"],
+        queue_target: 10,
+        queue_interval: 10,
+        pool_size: 0
       )
 
+    conn = start_supervised!({Xandra, options})
+
     assert {:error, %DBConnection.ConnectionError{}} = Xandra.execute(conn, "USE some_keyspace")
   end
 end