Add more directory fallbacks Loader session

Author: tjelvar-olsson

schema_salad/ref_resolver.py

@@ -204,9 +204,19 @@ def __init__(self,
         else:
             self.cache = {}
 
-        if (session is None) and ("HOME" in os.environ):
-            self.session = CacheControl(requests.Session(),
-                                   cache=FileCache(os.path.join(os.environ["HOME"], ".cache", "salad")))
+        if session is None:
+            if "HOME" in os.environ:
+                self.session = CacheControl(
+                    requests.Session(),
+                    cache=FileCache(os.path.join(os.environ["HOME"], ".cache", "salad")))
+            elif "TMP" in os.environ:
+                self.session = CacheControl(
+                    requests.Session(),
+                    cache=FileCache(os.path.join(os.environ["TMP"], ".cache", "salad")))
+            else:
+                self.session = CacheControl(
+                    requests.Session(),
+                    cache=FileCache("/tmp", ".cache", "salad"))
         else:
             self.session = session
 

schema_salad/tests/test_ref_resolver.py

@@ -1,10 +1,54 @@
 """Test the ref_resolver module."""
 
-def test_Loader_initialisation_when_HOME_env_is_missing():
+import shutil
+import tempfile
+
+import pytest  # type: ignore
+
+@pytest.fixture
+def tmp_dir_fixture(request):
+    d = tempfile.mkdtemp()
+
+    @request.addfinalizer
+    def teardown():
+        shutil.rmtree(d)
+    return d
+
+def test_Loader_initialisation_for_HOME_env_var(tmp_dir_fixture):
+    import os
     from schema_salad.ref_resolver import Loader
+    from requests import Session
+
+    # Ensure HOME is set.
+    os.environ["HOME"] = tmp_dir_fixture
+
+    loader = Loader(ctx={})
+    assert isinstance(loader.session, Session)
+
+def test_Loader_initialisation_for_TMP_env_var(tmp_dir_fixture):
     import os
+    from schema_salad.ref_resolver import Loader
+    from requests import Session
 
-    # Simulate missing HOME environment variable.
+    # Ensure HOME is missing.
     if "HOME" in os.environ:
         del os.environ["HOME"]
-    Loader(ctx={})
+    # Ensure TMP is present.
+    os.environ["TMP"] = tmp_dir_fixture
+
+    loader = Loader(ctx={})
+    assert isinstance(loader.session, Session)
+
+def test_Loader_initialisation_with_neither_TMP_HOME_set(tmp_dir_fixture):
+    import os
+    from schema_salad.ref_resolver import Loader
+    from requests import Session
+
+    # Ensure HOME is missing.
+    if "HOME" in os.environ:
+        del os.environ["HOME"]
+    if "TMP" in os.environ:
+        del os.environ["TMP"]
+
+    loader = Loader(ctx={})
+    assert isinstance(loader.session, Session)