Fix: Allow the usage of frozenset in the isin(...) and `notin(...…

…)` functions (kayak#744)

* Allow the usage of frozenset in the isin(...) and notin(...) functions

* Added more tests for the isin function

pypika/terms.py

@@ -184,12 +184,12 @@ def as_of(self, expr: str) -> "BasicCriterion":
     def all_(self) -> "All":
         return All(self)
 
-    def isin(self, arg: Union[list, tuple, set, "Term"]) -> "ContainsCriterion":
-        if isinstance(arg, (list, tuple, set)):
+    def isin(self, arg: Union[list, tuple, set, frozenset, "Term"]) -> "ContainsCriterion":
+        if isinstance(arg, (list, tuple, set, frozenset)):
             return ContainsCriterion(self, Tuple(*[self.wrap_constant(value) for value in arg]))
         return ContainsCriterion(self, arg)
 
-    def notin(self, arg: Union[list, tuple, set, "Term"]) -> "ContainsCriterion":
+    def notin(self, arg: Union[list, tuple, set, frozenset, "Term"]) -> "ContainsCriterion":
         return self.isin(arg).negate()
 
     def bin_regex(self, pattern: str) -> "BasicCriterion":

pypika/tests/test_criterions.py

@@ -438,6 +438,12 @@ def test__function_isin(self):
         self.assertEqual('COALESCE("foo",0) IN (0,1)', str(c1))
         self.assertEqual('COALESCE("isin"."foo",0) IN (0,1)', str(c2))
 
+        for t in (list, tuple, set, frozenset):
+            c_type = fn.Coalesce(Field("foo"), 0).isin(t([0, 1]))
+            self.assertEqual('COALESCE("foo",0) IN (0,1)', str(c_type))
+
+        self.assertRaises(AttributeError, lambda: str(fn.Coalesce(Field("foo"), 0).isin('SHOULD_FAIL')))
+
     def test__in_unicode(self):
         c1 = Field("foo").isin([u"a", u"b"])
         c2 = Field("foo", table=self.t).isin([u"a", u"b"])