public void Malformed_Weird() { var empty = new EmptyEnumerable <int>(); var emptyOrdered = new EmptyOrderedEnumerable <int>(); var groupByDefault = new GroupByDefaultEnumerable <int, int, int, EmptyEnumerable <int>, EmptyEnumerator <int> >(); var groupBySpecific = new GroupBySpecificEnumerable <int, int, int, EmptyEnumerable <int>, EmptyEnumerator <int> >(); var lookupDefault = new LookupDefaultEnumerable <int, int>(); var lookupSpecific = new LookupSpecificEnumerable <int, int>(); var range = new RangeEnumerable(); var repeat = new RepeatEnumerable <int>(); var reverseRange = new ReverseRangeEnumerable(); var oneItemDefault = new OneItemDefaultEnumerable <int>(); var oneItemSpecific = new OneItemSpecificEnumerable <int>(); var oneItemDefaultOrdered = new OneItemDefaultOrderedEnumerable <int>(); var oneItemSpecificOrdered = new OneItemSpecificOrderedEnumerable <int>(); // empty { try { empty.First(); Assert.Fail(); }catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { empty.First(x => true); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { empty.FirstOrDefault(); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { empty.FirstOrDefault(x => true); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } } // emptyOrdered { try { emptyOrdered.First(); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { emptyOrdered.First(x => true); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { emptyOrdered.FirstOrDefault(); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { emptyOrdered.FirstOrDefault(x => true); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } } // groupByDefault { try { groupByDefault.First(); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { groupByDefault.First(x => true); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { groupByDefault.FirstOrDefault(); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { groupByDefault.FirstOrDefault(x => true); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } } // groupBySpecific { try { groupBySpecific.First(); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { groupBySpecific.First(x => true); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { groupBySpecific.FirstOrDefault(); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { groupBySpecific.FirstOrDefault(x => true); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } } // lookupDefault { try { lookupDefault.First(); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { lookupDefault.First(x => true); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { lookupDefault.FirstOrDefault(); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { lookupDefault.FirstOrDefault(x => true); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } } // lookupSpecific { try { lookupSpecific.First(); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { lookupSpecific.First(x => true); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { lookupSpecific.FirstOrDefault(); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { lookupSpecific.FirstOrDefault(x => true); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } } // range { try { range.First(); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { range.First(x => true); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { range.FirstOrDefault(); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { range.FirstOrDefault(x => true); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } } // repeat { try { repeat.First(); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { repeat.First(x => true); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { repeat.FirstOrDefault(); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { repeat.FirstOrDefault(x => true); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } } // reverseRange { try { reverseRange.First(); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { reverseRange.First(x => true); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { reverseRange.FirstOrDefault(); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { reverseRange.FirstOrDefault(x => true); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } } // oneItemDefault { try { oneItemDefault.First(); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { oneItemDefault.First(x => true); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { oneItemDefault.FirstOrDefault(); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { oneItemDefault.FirstOrDefault(x => true); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } } // oneItemSpecific { try { oneItemSpecific.First(); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { oneItemSpecific.First(x => true); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { oneItemSpecific.FirstOrDefault(); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { oneItemSpecific.FirstOrDefault(x => true); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } } // oneItemDefaultOrdered { try { oneItemDefaultOrdered.First(); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { oneItemDefaultOrdered.First(x => true); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { oneItemDefaultOrdered.FirstOrDefault(); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { oneItemDefaultOrdered.FirstOrDefault(x => true); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } } // oneItemSpecificOrdered { try { oneItemSpecificOrdered.First(); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { oneItemSpecificOrdered.First(x => true); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { oneItemSpecificOrdered.FirstOrDefault(); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } try { oneItemSpecificOrdered.FirstOrDefault(x => true); Assert.Fail(); } catch (ArgumentException exc) { Assert.AreEqual("source", exc.ParamName); } } }