System.Linq.Tests.WhereTests.Where_SourceThrowsOnGetEnumerator C# (CSharp) Method

        public void Where_SourceThrowsOnGetEnumerator()
        {
            IEnumerable<int> source = new ThrowsOnGetEnumerator();
            Func<int, bool> truePredicate = (value) => true;

            var enumerator = source.Where(truePredicate).GetEnumerator();

            // Ensure the first MoveNext call throws an exception
            Assert.Throws<InvalidOperationException>(() => enumerator.MoveNext());

            // Ensure Current is set to the default value of type T
            int currentValue = enumerator.Current;
            Assert.Equal(default(int), currentValue);
            
            // Ensure subsequent MoveNext calls succeed
            Assert.True(enumerator.MoveNext());
            Assert.Equal(1, enumerator.Current);
        }