add crds to downstream

.github/workflows/downstream.yml

@@ -51,6 +51,7 @@ jobs:
       # Any env name which does not start with `pyXY` will use this Python version.
       default_python: '3.10'
       envs: |
+        - linux: crds
         - linux: gwcs
         - linux: jwst
         - linux: stdatamodels

tox.ini

@@ -4,6 +4,7 @@ env_list =
     coverage
     py{39,310,311,312}{,-compatibility,-coverage,-jsonschema}{,-devdeps}{,-parallel}
     asdf{-standard,-transform-schemas,-unit-schemas,-wcs-schemas,-coordinates-schemas,-astropy}
+    crds
     gwcs
     jwst
     stdatamodels
@@ -158,6 +159,21 @@ commands_pre =
 commands =
     pytest specutils
 
+[testenv:crds]
+change_dir = {env_tmp_dir}
+allowlist_externals =
+    git
+    bash
+extras =
+commands_pre =
+    bash -c "pip freeze -q | grep 'asdf @' > {env_tmp_dir}/requirements.txt"
+    git clone https://github.com/spacetelescope/crds.git
+    pip install -e crds[test]
+    pip install -r {env_tmp_dir}/requirements.txt
+    pip freeze
+commands =
+    pytest crds
+
 [testenv:gwcs]
 change_dir = {env_tmp_dir}
 allowlist_externals =