diff --git a/tests/test_streaming_client.py b/tests/test_streaming_client.py
index cf1c6a5..c196c56 100644
--- a/tests/test_streaming_client.py
+++ b/tests/test_streaming_client.py
@@ -3,7 +3,6 @@
 import asyncio
 import sys
 import tempfile
-import textwrap
 from pathlib import Path
 from unittest.mock import AsyncMock, patch
 
@@ -373,80 +372,6 @@ class TestClaudeSDKClientStreaming:
 class TestQueryWithAsyncIterable:
     """Test query() function with async iterable inputs."""
 
-    def _create_test_script(
-        self, expected_messages=None, response=None, should_error=False
-    ):
-        """Create a test script that validates CLI args and stdin messages.
-
-        Args:
-            expected_messages: List of expected message content strings, or None to skip validation
-            response: Custom response to output, defaults to a success result
-            should_error: If True, script will exit with error after reading stdin
-
-        Returns:
-            Path to the test script
-        """
-        if response is None:
-            response = '{"type": "result", "subtype": "success", "duration_ms": 100, "duration_api_ms": 50, "is_error": false, "num_turns": 1, "session_id": "test", "total_cost_usd": 0.001}'
-
-        script_content = textwrap.dedent(
-            """
-            #!/usr/bin/env python3
-            import sys
-            import json
-            import time
-
-            # Check command line args
-            args = sys.argv[1:]
-            assert "--output-format" in args
-            assert "stream-json" in args
-
-            # Read stdin messages
-            stdin_messages = []
-            stdin_closed = False
-            try:
-                while True:
-                    line = sys.stdin.readline()
-                    if not line:
-                        stdin_closed = True
-                        break
-                    stdin_messages.append(line.strip())
-            except:
-                stdin_closed = True
-            """,
-        )
-
-        if expected_messages is not None:
-            script_content += textwrap.dedent(
-                f"""
-                # Verify we got the expected messages
-                assert len(stdin_messages) == {len(expected_messages)}
-                """,
-            )
-            for i, msg in enumerate(expected_messages):
-                script_content += f'''assert '"{msg}"' in stdin_messages[{i}]\n'''
-
-        if should_error:
-            script_content += textwrap.dedent(
-                """
-                sys.exit(1)
-                """,
-            )
-        else:
-            script_content += textwrap.dedent(
-                f"""
-                # Output response
-                print('{response}')
-                """,
-            )
-
-        with tempfile.NamedTemporaryFile(mode="w", suffix=".py", delete=False) as f:
-            test_script = f.name
-            f.write(script_content)
-
-        Path(test_script).chmod(0o755)
-        return test_script
-
     def test_query_with_async_iterable(self):
         """Test query with async iterable of messages."""
 
@@ -455,32 +380,63 @@ class TestQueryWithAsyncIterable:
                 yield {"type": "user", "message": {"role": "user", "content": "First"}}
                 yield {"type": "user", "message": {"role": "user", "content": "Second"}}
 
-            test_script = self._create_test_script(
-                expected_messages=["First", "Second"]
-            )
+            # Create a simple test script that validates stdin and outputs a result
+            with tempfile.NamedTemporaryFile(mode="w", suffix=".py", delete=False) as f:
+                test_script = f.name
+                f.write("""#!/usr/bin/env python3
+import sys
+import json
+
+# Read stdin messages
+stdin_messages = []
+while True:
+    line = sys.stdin.readline()
+    if not line:
+        break
+    stdin_messages.append(line.strip())
+
+# Verify we got 2 messages
+assert len(stdin_messages) == 2
+assert '"First"' in stdin_messages[0]
+assert '"Second"' in stdin_messages[1]
+
+# Output a valid result
+print('{"type": "result", "subtype": "success", "duration_ms": 100, "duration_api_ms": 50, "is_error": false, "num_turns": 1, "session_id": "test", "total_cost_usd": 0.001}')
+""")
+            
+            Path(test_script).chmod(0o755)
 
             try:
-                # Mock _build_command to return our test script
+                # Mock _find_cli to return python executing our test script
                 with patch.object(
                     SubprocessCLITransport,
-                    "_build_command",
-                    return_value=[
-                        sys.executable,
-                        test_script,
-                        "--output-format",
-                        "stream-json",
-                        "--verbose",
-                    ],
+                    "_find_cli",
+                    return_value=sys.executable
                 ):
-                    # Run query with async iterable
-                    messages = []
-                    async for msg in query(prompt=message_stream()):
-                        messages.append(msg)
+                    # Mock _build_command to add our test script as first argument
+                    original_build_command = SubprocessCLITransport._build_command
+                    
+                    def mock_build_command(self):
+                        # Get original command
+                        cmd = original_build_command(self)
+                        # Replace the CLI path with python + script
+                        cmd[0] = test_script
+                        return cmd
+                    
+                    with patch.object(
+                        SubprocessCLITransport,
+                        "_build_command",
+                        mock_build_command
+                    ):
+                        # Run query with async iterable
+                        messages = []
+                        async for msg in query(prompt=message_stream()):
+                            messages.append(msg)
 
-                    # Should get the result message
-                    assert len(messages) == 1
-                    assert isinstance(messages[0], ResultMessage)
-                    assert messages[0].subtype == "success"
+                        # Should get the result message
+                        assert len(messages) == 1
+                        assert isinstance(messages[0], ResultMessage)
+                        assert messages[0].subtype == "success"
             finally:
                 # Clean up
                 Path(test_script).unlink()