Fix apex_sepolicy_tests_test

In QueryTERule(), scontext argument works like OR-set while the test
rules should treat them as AND-set.

Bug: 285075529
Test: apex_sepolicy_tests_test
Change-Id: Ie33b8dd6bf62db67ad3762835c1500c81d975707
diff --git a/tests/apex_sepolicy_tests.py b/tests/apex_sepolicy_tests.py
index 0bcc998..c8ecc60 100644
--- a/tests/apex_sepolicy_tests.py
+++ b/tests/apex_sepolicy_tests.py
@@ -83,14 +83,16 @@
     """Returns error message if scontext can't read the target"""
     match rule:
         case AllowRead(tclass, scontext):
-            te_rules = list(pol.QueryTERule(scontext=scontext,
-                                            tcontext={tcontext},
-                                            tclass={tclass},
-                                            perms={'read'}))
-            if len(te_rules) > 0:
-                return []  # no errors
+            # Test every source in scontext(set)
+            for s in scontext:
+                te_rules = list(pol.QueryTERule(scontext={s},
+                                                tcontext={tcontext},
+                                                tclass={tclass},
+                                                perms={'read'}))
+                if len(te_rules) > 0:
+                    return []  # no errors
 
-            return [f"Error: {path}: {scontext} can't read. (tcontext={tcontext})"]
+                return [f"Error: {path}: {s} can't read. (tcontext={tcontext})"]
 
 
 rules = [