test to ensure all expected io is registered

Signed-off-by: Nathaniel Starkman (@nstarman) <[email protected]>

Author: nstarman

astropy/cosmology/io/tests/test_.py

@@ -0,0 +1,27 @@
+# Licensed under a 3-clause BSD style license - see LICENSE.rst
+
+"""Test that all expected methods are present, before I/O tests import.
+
+This file is weirdly named so that it's the first test of I/O.
+"""
+
+from astropy.cosmology.connect import convert_registry, readwrite_registry
+
+
+def test_expected_readwrite_io():
+    """Test that ONLY the expected I/O is registered."""
+
+    got = {k for k, _ in readwrite_registry._readers.keys()}
+    expected = {"ascii.ecsv"}
+
+    assert got == expected
+
+
+def test_expected_convert_io():
+    """Test that ONLY the expected I/O is registered."""
+
+    got = {k for k, _ in convert_registry._readers.keys()}
+    expected = {"astropy.cosmology", "mapping", "astropy.model", "astropy.row",
+                "astropy.table", "yaml"}
+
+    assert got == expected