Improve tests by using both Random methods

Author: J Burnett

test/IntListRandomizerTests.cs

@@ -26,21 +26,16 @@ public IntListRandomizerTests(IntListTestFixture testData)
 		[Fact]
 		public void random_element_from_int_list()
 		{
+			IEnumerable<int> enr = _testData.TestList as IEnumerable<int>;
+
 			for (int i = 0; i < _testData.TestList.Count; ++i)
 			{
+				// Test via the method taking ICollection
 				int curr = _testData.TestList.Random();
 				curr.Should().BeGreaterOrEqualTo(IntListTestFixture.MinTestValue);
-			}
-		}
-
 
-		[Fact]
-		public void random_element_from_int_list_by_IEnumerable()
-		{
-			IEnumerable<int> enumr = _testData.TestList;
-			foreach (var itr in enumr)
-			{
-				int curr = enumr.Random();
+				// Test via the method taking IEnumerable
+				curr = enr.Random();
 				curr.Should().BeGreaterOrEqualTo(IntListTestFixture.MinTestValue);
 			}
 		}
@@ -53,43 +48,85 @@ public void random_element_from_single_item_list()
 			int knownInt = 7466;
 			List<int> list = new List<int>();
 			list.Add(knownInt);
+			IEnumerable<int> enr = list as IEnumerable<int>;
 
 			// Get random from the list several times. Should only receive the single element.
 			for (int i = 0; i < 5; ++i)
 			{
+				// Test via the method taking ICollection
 				(list.Random()).Should().Be(knownInt);
+
+				// Test via the method taking IEnumerable
+				(enr.Random()).Should().Be(knownInt);
 			}
 		}
 
 
 		[Fact]
-		public void random_element_from_()
+		public void random_element_from_Dictionary()
 		{
+			// Create a collection with asso'd enumerator, and populate it.
+			Dictionary<int, string> dict = new Dictionary<int, string>();
+			IEnumerable<KeyValuePair<int, string>> enr = dict as IEnumerable<KeyValuePair<int, string>>;
+			for (int i = 0; i < 250; ++i) { dict.Add(i, i.ToString()); }
+
+
+			for (int i = 0; i < dict.Count; ++i)
+			{
+				// Test via the method taking ICollection
+				var curr = dict.Random();
+				curr.Key.Should().BeGreaterOrEqualTo(IntListTestFixture.MinTestValue);
+				curr.Value.Should().BeEquivalentTo(curr.Key.ToString());
+
+				// Test via the method taking IEnumerable
+				curr = enr.Random();
+				curr.Key.Should().BeGreaterOrEqualTo(IntListTestFixture.MinTestValue);
+				curr.Value.Should().BeEquivalentTo(curr.Key.ToString());
+			}
+		}
+
+
+		[Fact]
+		public void random_element_from_SortedList()
+		{
+			// Create a collection with asso'd enumerator, and populate it.
 			SortedList<int, string> list = new SortedList<int, string>();
+			IEnumerable<KeyValuePair<int, string>> enr = list as IEnumerable<KeyValuePair<int, string>>;
 			for (int i = 0; i < 250; ++i) { list.Add(i, i.ToString()); }
 
-			// Get random elements from ~1/10 of the list.  The probability of sequential duplicates
-			//	increases when covering more of the available elements.
 			for (int i = 0; i < list.Count; ++i)
 			{
+				// Test via the method taking ICollection
 				var curr = list.Random();
 				curr.Key.Should().BeGreaterOrEqualTo(IntListTestFixture.MinTestValue);
 				curr.Value.Should().BeEquivalentTo(curr.Key.ToString());
+
+				// Test via the method taking IEnumerable
+				curr = enr.Random();
+				curr.Key.Should().BeGreaterOrEqualTo(IntListTestFixture.MinTestValue);
+				curr.Value.Should().BeEquivalentTo(curr.Key.ToString());
 			}
 		}
 
 		#endregion Positive tests
 
 
+
 		#region Negative tests
 
 		// Verify the correct exception occurs when passed an empty list
 		[Fact]
 		public void verify_excp_on_empty_list()
 		{
 			List<string> list = new List<string>();
+
+			// Test via the method taking ICollection
 			Action act = () => list.Random();
 			act.ShouldThrow<ArgumentOutOfRangeException>();
+
+			// Test via the method taking IEnumerable
+			act = () => (list as IEnumerable<string>).Random();
+			act.ShouldThrow<ArgumentOutOfRangeException>();
 		}
 
 		#endregion Negative tests

test/IntListTestFixture.cs

@@ -17,7 +17,7 @@ public class IntListTestFixture : IDisposable
         public IntListTestFixture()
         {
 			TestList = new List<int>();
-			for (int i = MinTestValue; i < MaxTestValue; ++i)
+			for (int i = MinTestValue; i <= MaxTestValue; ++i)
             {
                 TestList.Add(i);
             }