feat(V2): error envelope module estratto da server.py

tests/unit/common/test_errors.py

@@ -0,0 +1,29 @@
+from __future__ import annotations
+
+from cerbero_mcp.common.errors import error_envelope, HTTP_CODE_MAP
+
+
+def test_envelope_minimal():
+    e = error_envelope(type_="x", code="C", message="m", retryable=False)
+    assert e["error"]["code"] == "C"
+    assert e["error"]["retryable"] is False
+    assert "request_id" in e
+    assert "data_timestamp" in e
+
+
+def test_envelope_with_suggested_fix_and_details():
+    e = error_envelope(
+        type_="validation_error",
+        code="INVALID_INPUT",
+        message="bad",
+        retryable=False,
+        suggested_fix="check field x",
+        details={"field": "x"},
+    )
+    assert e["error"]["suggested_fix"] == "check field x"
+    assert e["error"]["details"] == {"field": "x"}
+
+
+def test_http_code_map_has_common_codes():
+    assert HTTP_CODE_MAP[401] == "UNAUTHORIZED"
+    assert HTTP_CODE_MAP[502] == "UPSTREAM_ERROR"