Fix memory leak: Dispose IronCompressResult in Zstd codec (#7193)

* Initial plan

* Fix memory leak: Dispose IronCompressResult in Zstd codec and add tests

Co-authored-by: sfmskywalker <938393+sfmskywalker@users.noreply.github.com>

* Refactor tests to be more DRY using Theory and InlineData

Co-authored-by: sfmskywalker <938393+sfmskywalker@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: sfmskywalker <938393+sfmskywalker@users.noreply.github.com>

src/modules/Elsa.Common/Codecs/Zstd.cs

@@ -15,7 +15,7 @@ public class Zstd : ICompressionCodec
     {
         var inputBytes = Encoding.UTF8.GetBytes(input);
         var span = inputBytes.AsSpan();
-        var result = Iron.Compress(Codec.Zstd, span);
+        using var result = Iron.Compress(Codec.Zstd, span);
         var compressedBytes = result.AsSpan();
         var compressedString = Convert.ToBase64String(compressedBytes);
         
@@ -27,7 +27,7 @@ public class Zstd : ICompressionCodec
     {
         var inputBytes = Convert.FromBase64String(input);
         var span = inputBytes.AsSpan();
-        var result = Iron.Decompress(Codec.Zstd, span);
+        using var result = Iron.Decompress(Codec.Zstd, span);
         var decompressedBytes = result.AsSpan();
         var decompressedString = Encoding.UTF8.GetString(decompressedBytes);
         

test/unit/Elsa.Common.UnitTests/Codecs/ZstdTests.cs

@@ -0,0 +1,67 @@
+using Elsa.Common.Codecs;
+
+namespace Elsa.Common.UnitTests.Codecs;
+
+public class ZstdTests
+{
+    private readonly Zstd _codec = new();
+
+    [Fact]
+    public async Task CompressAsync_WithSimpleString_ReturnsCompressedString()
+    {
+        // Arrange
+        var input = "Hello, World!";
+
+        // Act
+        var result = await _codec.CompressAsync(input);
+
+        // Assert
+        Assert.NotNull(result);
+        Assert.NotEmpty(result);
+        Assert.NotEqual(input, result);
+    }
+
+    [Theory]
+    [InlineData("Hello, World!")]
+    [InlineData("")]
+    [InlineData("Hello! 你好! مرحبا! Здравствуйте! 🎉🎊")]
+    [InlineData("{\"name\":\"John Doe\",\"age\":30,\"city\":\"New York\",\"items\":[1,2,3,4,5]}")]
+    public async Task CompressDecompress_RoundTrip_PreservesOriginalData(string original)
+    {
+        // Act
+        var compressed = await _codec.CompressAsync(original);
+        var decompressed = await _codec.DecompressAsync(compressed);
+
+        // Assert
+        Assert.Equal(original, decompressed);
+    }
+
+    [Fact]
+    public async Task CompressDecompress_WithLargeString_WorksCorrectly()
+    {
+        // Arrange
+        var original = string.Join("", Enumerable.Repeat("This is a test string that will be compressed. ", 1000));
+
+        // Act
+        var compressed = await _codec.CompressAsync(original);
+        var decompressed = await _codec.DecompressAsync(compressed);
+
+        // Assert
+        Assert.Equal(original, decompressed);
+        Assert.True(compressed.Length < original.Length, "Compressed string should be smaller than original");
+    }
+
+    [Fact]
+    public async Task CompressAsync_MultipleCallsWithSameInput_ProducesConsistentResults()
+    {
+        // Arrange
+        var input = "Test string for consistency";
+
+        // Act
+        var result1 = await _codec.CompressAsync(input);
+        var result2 = await _codec.CompressAsync(input);
+
+        // Assert
+        Assert.Equal(result1, result2);
+    }
+}