Extract weighted partitioning into WeightedLfuCapacityPartition

BitFaster.Caching.UnitTests/Lfu/WeightedLfuCapacityPartitionTests.cs

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+using BitFaster.Caching.Lfu;
+using FluentAssertions;
+using Xunit;
+
+namespace BitFaster.Caching.UnitTests.Lfu
+{
+    public class WeightedLfuCapacityPartitionTests
+    {
+        [Fact]
+        public void CapacityReturnsCapacity()
+        {
+            var partition = new WeightedLfuCapacityPartition(123);
+            partition.Capacity.Should().Be(123);
+        }
+
+        [Fact]
+        public void MaximumEqualsCapacity()
+        {
+            var partition = new WeightedLfuCapacityPartition(100);
+            partition.Maximum.Should().Be(100);
+        }
+
+        [Theory]
+        [InlineData(3, 1, 1)]
+        [InlineData(100, 1, 79)]
+        [InlineData(1000, 10, 792)]
+        public void CtorSetsExpectedWeightedMaximums(int capacity, long expectedWindowMaximum, long expectedMainProtectedMaximum)
+        {
+            var partition = new WeightedLfuCapacityPartition(capacity);
+
+            partition.Maximum.Should().Be(capacity);
+            partition.WindowMaximum.Should().Be(expectedWindowMaximum);
+            partition.MainProtectedMaximum.Should().Be(expectedMainProtectedMaximum);
+        }
+    }
+}