Revert sdist check to make it more testable

Signed-off-by: Juan Luis Cano Rodríguez <juan_luis_cano@mckinsey.com>

kedro/framework/cli/micropkg.py

@@ -415,11 +415,10 @@ def _unpack_sdist(location: str, destination: Path, fs_args: str | None) -> None
         sdist_file = list(destination.glob("*.tar.gz"))
         # `--no-deps --no-binary :all:` should fetch only one source distribution file,
         # and CLI should fail if that's not the case.
-        # No need to check for zero sdists, in that case the previous command would fail.
-        if len(sdist_file) > 1:
+        if len(sdist_file) != 1:
             file_names = [sf.name for sf in sdist_file]
             raise KedroCliError(
-                f"More than 1 sdist files found: {file_names}. "
+                f"More than 1 or no sdist files found: {file_names}. "
                 f"There has to be exactly one source distribution file."
             )
         with tarfile.open(sdist_file[0], "r:gz") as fs_file:

tests/framework/cli/micropkg/test_micropkg_pull.py

@@ -708,14 +708,14 @@ def test_pull_from_pypi_more_than_one_sdist_file(
         )
 
         assert result.exit_code
-        assert "Error: More than 1 sdist files found:" in result.output
+        assert "Error: More than 1 or no sdist files found:" in result.output
 
     def test_pull_unsupported_protocol_by_fsspec(
         self, fake_project_cli, fake_metadata, tmp_path, mocker
     ):
         protocol = "unsupported"
         exception_message = f"Protocol not known: {protocol}"
-        error_message = "Error: More than 1 sdist files found:"
+        error_message = "Error: More than 1 or no sdist files found:"
         package_path = f"{protocol}://{PIPELINE_NAME}"
 
         python_call_mock = mocker.patch("kedro.framework.cli.micropkg.python_call")