diff --git a/src/flatcollections-array/FlatArray.Tests/Internal.Helper/FlatArray/FlatArray.Verify.cs b/src/flatcollections-array/FlatArray.Tests/Internal.Helper/FlatArray/FlatArray.Verify.cs
index d862831a..bbbe6179 100644
--- a/src/flatcollections-array/FlatArray.Tests/Internal.Helper/FlatArray/FlatArray.Verify.cs
+++ b/src/flatcollections-array/FlatArray.Tests/Internal.Helper/FlatArray/FlatArray.Verify.cs
@@ -29,9 +29,9 @@ internal static void VerifyTruncatedState<T>(this FlatArray<T> actual, params T[
         Assert.StrictEqual(expectedItems?.Length ?? default, actualLength);
 
         var actualItems = actual.GetFieldValue<T[]?>("items");
-        if (actualItems is null || actualItems.Length == actualLength)
+        if (actualItems is null)
         {
-            Assert.Equal(expectedItems, actualItems);
+            Assert.Null(expectedItems);
             return;
         }
 
diff --git a/src/flatcollections-array/FlatArray.Tests/Tests.FlatArray.T/Cast/CastArray.cs b/src/flatcollections-array/FlatArray.Tests/Tests.FlatArray.T/Cast/CastArray.cs
new file mode 100644
index 00000000..fbaf5cb3
--- /dev/null
+++ b/src/flatcollections-array/FlatArray.Tests/Tests.FlatArray.T/Cast/CastArray.cs
@@ -0,0 +1,76 @@
+using System;
+using Xunit;
+using static PrimeFuncPack.UnitTest.TestData;
+
+namespace PrimeFuncPack.Core.Tests;
+
+partial class FlatArrayTest
+{
+    [Theory]
+    [InlineData(false)]
+    [InlineData(true)]
+    public static void CastArray_CastIsInvalid_ExpectInvalidCastException(
+        bool isSourceDefault)
+    {
+        var source = isSourceDefault ? default : new[] { PlusFifteen, Zero }.InitializeFlatArray();
+        _ = Assert.Throws<InvalidCastException>(Test);
+
+        void Test()
+            =>
+            _ = source.CastArray<string>();
+    }
+
+    [Theory]
+    [MemberData(nameof(CastArray_CastValueTypeIsValid_ExpectCastedInnerState_TestSource))]
+    public static void CastArray_CastValueTypeIsValid_ExpectCastedInnerState(
+        FlatArray<int> source, uint[]? expectedItems)
+    {
+        var actual = source.CastArray<uint>();
+        actual.VerifyTruncatedState(expectedItems);
+    }
+
+    [Theory]
+    [MemberData(nameof(CastArray_CastRefTypeIsValid_ExpectCastedInnerState_TestSource))]
+    public static void CastArray_CastRefTypeIsValid_ExpectCastedInnerState(
+        FlatArray<string?> source, object?[]? expectedItems)
+    {
+        var actual = source.CastArray<object?>();
+        actual.VerifyTruncatedState(expectedItems);
+    }
+
+    public static TheoryData<FlatArray<int>, uint[]?> CastArray_CastValueTypeIsValid_ExpectCastedInnerState_TestSource
+        =>
+        new()
+        {
+            {
+                default,
+                default
+            },
+            {
+                new int[] { PlusFifteen, Zero, One }.InitializeFlatArray(),
+                [ PlusFifteen, Zero, One ]
+            },
+            {
+                new int[] { int.MaxValue, One, PlusFifteen, Zero, MinusOne }.InitializeFlatArray(4),
+                [ int.MaxValue, One, PlusFifteen, Zero ]
+            }
+        };
+
+    public static TheoryData<FlatArray<string?>, object?[]?> CastArray_CastRefTypeIsValid_ExpectCastedInnerState_TestSource
+        =>
+        new()
+        {
+            {
+                default,
+                default
+            },
+            {
+                new string?[] { SomeString, null }.InitializeFlatArray(),
+                [ SomeString, null ]
+            },
+            {
+                new string?[] { null, AnotherString, EmptyString, UpperAnotherString, WhiteSpaceString }.InitializeFlatArray(3),
+                [ null, AnotherString, EmptyString ]
+            }
+        };
+}
\ No newline at end of file
diff --git a/src/flatcollections-array/FlatArray.Tests/Tests.FlatArray.T/Cast/CastUp.cs b/src/flatcollections-array/FlatArray.Tests/Tests.FlatArray.T/Cast/CastUp.cs
new file mode 100644
index 00000000..f82b326f
--- /dev/null
+++ b/src/flatcollections-array/FlatArray.Tests/Tests.FlatArray.T/Cast/CastUp.cs
@@ -0,0 +1,35 @@
+using System;
+using Xunit;
+using static PrimeFuncPack.UnitTest.TestData;
+
+namespace PrimeFuncPack.Core.Tests;
+
+partial class FlatArrayTest
+{
+    [Theory]
+    [MemberData(nameof(CastUp_ExpectCorrectInnerState_TestSource))]
+    public static void CastUp_ExpectCorrectInnerState(
+        FlatArray<string?> source, object?[]? expectedItems)
+    {
+        var actual = FlatArray<object?>.CastUp(source);
+        actual.VerifyTruncatedState(expectedItems);
+    }
+
+    public static TheoryData<FlatArray<string?>, object?[]?> CastUp_ExpectCorrectInnerState_TestSource
+        =>
+        new()
+        {
+            {
+                default,
+                default
+            },
+            {
+                new string?[] { SomeString, EmptyString }.InitializeFlatArray(),
+                [ SomeString, EmptyString ]
+            },
+            {
+                new string?[] { AnotherString, UpperSomeString, null, WhiteSpaceString, SomeString, TabString }.InitializeFlatArray(5),
+                [ AnotherString, UpperSomeString, null, WhiteSpaceString, SomeString]
+            }
+        };
+}
\ No newline at end of file
diff --git a/src/flatcollections-array/FlatArray.Tests/Tests.FlatArray.T/Cast/TryCastArray.cs b/src/flatcollections-array/FlatArray.Tests/Tests.FlatArray.T/Cast/TryCastArray.cs
new file mode 100644
index 00000000..40de40fd
--- /dev/null
+++ b/src/flatcollections-array/FlatArray.Tests/Tests.FlatArray.T/Cast/TryCastArray.cs
@@ -0,0 +1,78 @@
+using System;
+using Xunit;
+using static PrimeFuncPack.UnitTest.TestData;
+
+namespace PrimeFuncPack.Core.Tests;
+
+partial class FlatArrayTest
+{
+    [Theory]
+    [InlineData(false)]
+    [InlineData(true)]
+    public static void TryCastArray_CastIsInvalid_ExpectNull(
+        bool isSourceDefault)
+    {
+        var source = isSourceDefault ? default : new[] { PlusFifteen, Zero }.InitializeFlatArray();
+        var actual = source.TryCastArray<string>();
+
+        Assert.Null(actual);
+    }
+
+    [Theory]
+    [MemberData(nameof(TryCastArray_CastValueTypeIsValid_ExpectCastedInnerState_TestSource))]
+    public static void TryCastArray_CastValueTypeIsValid_ExpectCastedInnerState(
+        FlatArray<int> source, uint[]? expectedItems)
+    {
+        var actual = source.TryCastArray<uint>();
+
+        Assert.NotNull(actual);
+        actual.Value.VerifyTruncatedState(expectedItems);
+    }
+
+    [Theory]
+    [MemberData(nameof(TryCastArray_CastRefTypeIsValid_ExpectCastedInnerState_TestSource))]
+    public static void TryCastArray_CastRefTypeIsValid_ExpectCastedInnerState(
+        FlatArray<string?> source, object?[]? expectedItems)
+    {
+        var actual = source.TryCastArray<object?>();
+
+        Assert.NotNull(actual);
+        actual.Value.VerifyTruncatedState(expectedItems);
+    }
+
+    public static TheoryData<FlatArray<int>, uint[]?> TryCastArray_CastValueTypeIsValid_ExpectCastedInnerState_TestSource
+        =>
+        new()
+        {
+            {
+                default,
+                default
+            },
+            {
+                new int[] { PlusFifteen, Zero, One }.InitializeFlatArray(),
+                [ PlusFifteen, Zero, One ]
+            },
+            {
+                new int[] { int.MaxValue, One, PlusFifteen, Zero, MinusOne }.InitializeFlatArray(4),
+                [ int.MaxValue, One, PlusFifteen, Zero ]
+            }
+        };
+
+    public static TheoryData<FlatArray<string?>, object?[]?> TryCastArray_CastRefTypeIsValid_ExpectCastedInnerState_TestSource
+        =>
+        new()
+        {
+            {
+                default,
+                default
+            },
+            {
+                new string?[] { SomeString, null }.InitializeFlatArray(),
+                [ SomeString, null ]
+            },
+            {
+                new string?[] { null, AnotherString, EmptyString, UpperAnotherString, WhiteSpaceString }.InitializeFlatArray(3),
+                [ null, AnotherString, EmptyString ]
+            }
+        };
+}
\ No newline at end of file
diff --git a/src/flatcollections-array/FlatArray.Tests/Tests.FlatArray/CastUp.cs b/src/flatcollections-array/FlatArray.Tests/Tests.FlatArray/CastUp.cs
new file mode 100644
index 00000000..5cd32cca
--- /dev/null
+++ b/src/flatcollections-array/FlatArray.Tests/Tests.FlatArray/CastUp.cs
@@ -0,0 +1,35 @@
+using System;
+using Xunit;
+using static PrimeFuncPack.UnitTest.TestData;
+
+namespace PrimeFuncPack.Core.Tests;
+
+partial class FlatArrayStaticTest
+{
+    [Theory]
+    [MemberData(nameof(CastUp_ExpectCorrectInnerState_TestSource))]
+    public static void CastUp_ExpectCorrectInnerState(
+        FlatArray<string?> source, object?[]? expectedItems)
+    {
+        var actual = FlatArray.CastUp<object?, string?>(source);
+        actual.VerifyTruncatedState(expectedItems);
+    }
+
+    public static TheoryData<FlatArray<string?>, object?[]?> CastUp_ExpectCorrectInnerState_TestSource
+        =>
+        new()
+        {
+            {
+                default,
+                default
+            },
+            {
+                new string?[] { SomeString, EmptyString }.InitializeFlatArray(),
+                [ SomeString, EmptyString ]
+            },
+            {
+                new string?[] { AnotherString, UpperSomeString, null, WhiteSpaceString, SomeString, TabString }.InitializeFlatArray(5),
+                [ AnotherString, UpperSomeString, null, WhiteSpaceString, SomeString]
+            }
+        };
+}
\ No newline at end of file
diff --git a/src/flatcollections-array/FlatArray/FlatArray.T/Cast/Cast.CastArray.Try.cs b/src/flatcollections-array/FlatArray/FlatArray.T/Cast/Cast.CastArray.Try.cs
new file mode 100644
index 00000000..2b2c36c5
--- /dev/null
+++ b/src/flatcollections-array/FlatArray/FlatArray.T/Cast/Cast.CastArray.Try.cs
@@ -0,0 +1,16 @@
+namespace System;
+
+partial struct FlatArray<T>
+{
+    public FlatArray<TResult>? TryCastArray<TResult>()
+    {
+        // Safe array cast: 'as' cast
+
+        if (InnerItems() is not TResult[] resultItems)
+        {
+            return null;
+        }
+
+        return new(length, items is null ? null : resultItems, default);
+    }
+}
diff --git a/src/flatcollections-array/FlatArray/FlatArray.T/FlatArray.CastArray.cs b/src/flatcollections-array/FlatArray/FlatArray.T/Cast/Cast.CastArray.cs
similarity index 55%
rename from src/flatcollections-array/FlatArray/FlatArray.T/FlatArray.CastArray.cs
rename to src/flatcollections-array/FlatArray/FlatArray.T/Cast/Cast.CastArray.cs
index 733232d4..d4263b2d 100644
--- a/src/flatcollections-array/FlatArray/FlatArray.T/FlatArray.CastArray.cs
+++ b/src/flatcollections-array/FlatArray/FlatArray.T/Cast/Cast.CastArray.cs
@@ -3,14 +3,11 @@
 partial struct FlatArray<T>
 {
     // TODO: Add the tests and make public
-    internal FlatArray<TResult> CastArray<TResult>()
+    public FlatArray<TResult> CastArray<TResult>()
     {
         // Unsafe array cast: InvalidCastException is expected
-
         var resultItems = (TResult[])(object)InnerItems();
 
-        var resultItemsNormalized = items is null ? null : resultItems;
-
-        return new(length, resultItemsNormalized, default);
+        return new(length, items is null ? null : resultItems, default);
     }
 }
diff --git a/src/flatcollections-array/FlatArray/FlatArray.T/FlatArray.CastUp.cs b/src/flatcollections-array/FlatArray/FlatArray.T/Cast/Cast.CastUp.cs
similarity index 55%
rename from src/flatcollections-array/FlatArray/FlatArray.T/FlatArray.CastUp.cs
rename to src/flatcollections-array/FlatArray/FlatArray.T/Cast/Cast.CastUp.cs
index fa8bd359..fbc49bba 100644
--- a/src/flatcollections-array/FlatArray/FlatArray.T/FlatArray.CastUp.cs
+++ b/src/flatcollections-array/FlatArray/FlatArray.T/Cast/Cast.CastUp.cs
@@ -2,8 +2,7 @@
 
 partial struct FlatArray<T>
 {
-    // TODO: Add the tests and make public
-    internal static FlatArray<T> CastUp<TDerived>(FlatArray<TDerived> items)
+    public static FlatArray<T> CastUp<TDerived>(FlatArray<TDerived> items)
         where TDerived : class?, T
         =>
         new(items.length, items.items, default);
diff --git a/src/flatcollections-array/FlatArray/FlatArray.T/FlatArray.CastArray.Try.cs b/src/flatcollections-array/FlatArray/FlatArray.T/FlatArray.CastArray.Try.cs
deleted file mode 100644
index f75907ff..00000000
--- a/src/flatcollections-array/FlatArray/FlatArray.T/FlatArray.CastArray.Try.cs
+++ /dev/null
@@ -1,19 +0,0 @@
-namespace System;
-
-partial struct FlatArray<T>
-{
-    // TODO: Add the tests and make public
-    internal FlatArray<TResult>? TryCastArray<TResult>()
-    {
-        // Safe array cast: 'as' cast
-
-        if (InnerItems() is not TResult[] resultItems)
-        {
-            return null;
-        }
-
-        var resultItemsNormalized = items is null ? null : resultItems;
-
-        return new(length, resultItemsNormalized, default);
-    }
-}
diff --git a/src/flatcollections-array/FlatArray/FlatArray/FlatArray.CastUp.cs b/src/flatcollections-array/FlatArray/FlatArray/FlatArray.CastUp.cs
index 9381301b..3261da07 100644
--- a/src/flatcollections-array/FlatArray/FlatArray/FlatArray.CastUp.cs
+++ b/src/flatcollections-array/FlatArray/FlatArray/FlatArray.CastUp.cs
@@ -2,8 +2,7 @@
 
 partial class FlatArray
 {
-    // TODO: Add the tests and make public
-    internal static FlatArray<T> CastUp<T, TDerived>(FlatArray<TDerived> items)
+    public static FlatArray<T> CastUp<T, TDerived>(FlatArray<TDerived> items)
         where TDerived : class?, T
         =>
         FlatArray<T>.CastUp(items);