raising ValueError for py38 or less for truss supported version (#1350)

* Adding error check

* Remain on prior version

* Fixing errors

truss/base/truss_config.py

@@ -891,11 +891,9 @@ def map_to_supported_python_version(python_version: str) -> str:
         return "py311"
 
     if python_minor_version < 8:
-        # TODO: consider raising an error instead - it doesn't' seem safe.
-        logger.info(
+        raise ValueError(
             f"Mapping python version {python_major_version}.{python_minor_version}"
             " to 3.8, the lowest version that Truss currently supports."
         )
-        return "py38"
 
     return python_version

truss/tests/test_model_inference.py

@@ -102,20 +102,38 @@ def _temp_truss(model_src: str, config_src: str = "") -> Iterator[TrussHandle]:
 @pytest.mark.parametrize(
     "python_version, expected_python_version",
     [
-        ("py37", "py38"),
         ("py38", "py38"),
         ("py39", "py39"),
         ("py310", "py310"),
         ("py311", "py311"),
         ("py312", "py311"),
-        ("py36", "py38"),
     ],
 )
 def test_map_to_supported_python_version(python_version, expected_python_version):
     out_python_version = map_to_supported_python_version(python_version)
     assert out_python_version == expected_python_version
 
 
+def test_not_supported_python_minor_versions():
+    with pytest.raises(
+        ValueError,
+        match="Mapping python version 3.6 to 3.8, "
+        "the lowest version that Truss currently supports.",
+    ):
+        map_to_supported_python_version("py36")
+    with pytest.raises(
+        ValueError,
+        match="Mapping python version 3.7 to 3.8, "
+        "the lowest version that Truss currently supports.",
+    ):
+        map_to_supported_python_version("py37")
+
+
+def test_not_supported_python_major_versions():
+    with pytest.raises(NotImplementedError, match="Only python version 3 is supported"):
+        map_to_supported_python_version("py211")
+
+
 @pytest.mark.integration
 def test_model_load_logs(test_data_path):
     model = """