Add tests (WIP)

python/ql/src/Exceptions/IncorrectExceptOrder.ql

@@ -1,5 +1,5 @@
 /**
- * @name Unreachable 'except' block
+ * @name Unreachable `except` block
  * @description Handling general exceptions before specific exceptions means that the specific
  *              handlers are never executed.
  * @kind problem
@@ -23,7 +23,7 @@ predicate builtinException(string name) {
 }
 
 predicate builtinExceptionSubclass(string base, string sub) {
-  typeModel("builtins." + base + "~Subclass", sub, "")
+  typeModel("builtins." + base + "~Subclass", "builtins." + sub, "")
 }
 
 newtype TExceptType =
@@ -48,7 +48,7 @@ class ExceptType extends TExceptType {
   DataFlow::Node getAUse() {
     result = classTracker(this.asClass())
     or
-    result = API::builtin(this.asBuiltinName()).asSource()
+    API::builtin(this.asBuiltinName()).asSource().flowsTo(result)
   }
 
   ExceptType getADirectSuperclass() {

python/ql/test/query-tests/Exceptions/general/IncorrectExceptOrder.qlref

@@ -1 +1,2 @@
-Exceptions/IncorrectExceptOrder.ql
+query: Exceptions/IncorrectExceptOrder.ql
+postprocess: utils/test/InlineExpectationsTestQuery.ql

python/ql/test/query-tests/Exceptions/general/exceptions_test.py

@@ -61,8 +61,34 @@ try:
     val.attr
 except Exception:
     print (2)
-except AttributeError:
+except AttributeError: # $Alert[py/unreachable-except]
     print (3)
+
+class MyExc(ValueError):
+    pass 
+
+try:
+    pass
+except ValueError:
+    pass 
+except MyExc: # $Alert[py/unreachable-except]
+    pass 
+
+class MyBaseExc(Exception):
+    pass 
+
+class MySubExc(MyBaseExc):
+    pass 
+
+try:
+    pass
+except MyBaseExc:
+    pass 
+except MySubExc: # $Alert[py/unreachable-except]
+    pass 
+except Exception:
+    pass
+
     
 #Catch BaseException
 def catch_base_exception():