Simplify block allocation logic

Recyclable.CollectionsTests/RecyclableDictionaryTests.cs

@@ -0,0 +1,85 @@
+using FluentAssertions;
+using Recyclable.Collections;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace Recyclable.CollectionsTests
+{
+    public class RecyclableDictionaryTests
+    {
+        private static readonly (int, string)[] _testData = new[] { (1, "a"), (2, "b"), (3, "c"), (4, "d"), (5, "e") };
+
+        [Fact]
+        public void AddShouldStoreItems()
+        {
+            using var dict = new RecyclableDictionary<int, string>();
+            foreach (var (key, value) in _testData)
+            {
+                dict.Add(key, value);
+            }
+
+            _ = dict.Should().HaveCount(_testData.Length);
+            for (var i = 0; i < _testData.Length; i++)
+            {
+                dict.GetKey(i).Should().Be(_testData[i].Item1);
+                dict.GetValue(i).Should().Be(_testData[i].Item2);
+            }
+        }
+
+        [Fact]
+        public void IndexerShouldUpdateValue()
+        {
+            using var dict = new RecyclableDictionary<int, string>();
+            dict.Add(1, "a");
+
+            dict[1] = "b";
+
+            _ = dict[1].Should().Be("b");
+        }
+
+        [Fact]
+        public void RemoveShouldSwapWithLast()
+        {
+            using var dict = new RecyclableDictionary<int, string>();
+            foreach (var (key, value) in _testData)
+            {
+                dict.Add(key, value);
+            }
+
+            dict.Remove(3).Should().BeTrue();
+            _ = dict.ContainsKey(3).Should().BeFalse();
+            _ = dict.Should().HaveCount(_testData.Length - 1);
+        }
+
+        [Fact]
+        public void TryGetValueShouldReturnValue()
+        {
+            using var dict = new RecyclableDictionary<int, string>();
+            dict.Add(1, "a");
+
+            var found = dict.TryGetValue(1, out var value);
+
+            _ = found.Should().BeTrue();
+            _ = value.Should().Be("a");
+        }
+
+        [Fact]
+        public void EnumeratorShouldYieldItems()
+        {
+            using var dict = new RecyclableDictionary<int, string>();
+            foreach (var (key, value) in _testData)
+            {
+                dict.Add(key, value);
+            }
+
+            var actual = new List<KeyValuePair<int, string>>();
+            var enumerator = dict.GetEnumerator();
+            while (enumerator.MoveNext())
+            {
+                actual.Add(enumerator.Current);
+            }
+
+            _ = actual.Should().ContainInConsecutiveOrder(_testData.Select(x => new KeyValuePair<int, string>(x.Item1, x.Item2)));
+        }
+    }
+}