diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index cf74ac60..fb55ae44 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -15,6 +15,10 @@ jobs:
       uses: actions/checkout@v3
       with:
         fetch-depth: 0
+    - name: Install Mono
+      run: |
+        sudo apt-get update
+        sudo apt-get install -y mono-complete
     - name: Setup .NET
       uses: actions/setup-dotnet@v2
       with:
diff --git a/src/Reveal.Sdk.Dom.Tests/Visualizations/VisualizationSpecs/SparklineVisualizationDataSpecFixture.cs b/src/Reveal.Sdk.Dom.Tests/Visualizations/VisualizationSpecs/SparklineVisualizationDataSpecFixture.cs
new file mode 100644
index 00000000..d60aa764
--- /dev/null
+++ b/src/Reveal.Sdk.Dom.Tests/Visualizations/VisualizationSpecs/SparklineVisualizationDataSpecFixture.cs
@@ -0,0 +1,66 @@
+using Newtonsoft.Json.Linq;
+using Reveal.Sdk.Dom.Core.Constants;
+using Reveal.Sdk.Dom.Visualizations;
+using Reveal.Sdk.Dom.Visualizations.VisualizationSpecs;
+using System.Collections.Generic;
+using Xunit;
+
+namespace Reveal.Sdk.Dom.Tests.Visualizations.VisualizationSpecs
+{
+    public class SparklineVisualizationDataSpecFixture
+    {
+        [Fact]
+        public void Constructor_FieldsHaveDefaultValue()
+        {
+            // Act
+            var sparklineVSDataSpec = new SparklineVisualizationDataSpec();
+
+            // Assert
+            Assert.Equal(SchemaTypeNames.SparklineVisualizationDataSpecType, sparklineVSDataSpec.SchemaTypeName);
+            Assert.Equal(IndicatorVisualizationType.LastMonths, sparklineVSDataSpec.IndicatorType);
+        }
+
+        [Fact]
+        public void ToJsonString_CreateCorrectJsonString_WithoutCondition()
+        {
+            // Arrange
+            var expectedJson = """
+                {
+                  "_type": "BubbleVisualizationDataSpecType",
+                  "NumberOfPeriods": 3,
+                  "ShowIndicator": false,
+                  "IndicatorType": "YearToDatePreviousYear",
+                  "Date": {
+                    "_type": "DimensionColumnSpecType"
+                  },
+                  "Value": [],
+                  "AdHocFields": 12,
+                  "FormatVersion": 2,
+                  "AdHocExpandedElements": [],
+                  "Rows": []
+                }
+                """;
+            var sparklineVSDataSpec = new SparklineVisualizationDataSpec()
+            {
+                AdHocExpandedElements = new List<AdHocExpandedElement>(),
+                AdHocFields = 12,
+                Date = new DimensionColumn(),
+                FormatVersion = 2,
+                IndicatorType = IndicatorVisualizationType.YearToDatePreviousYear,
+                NumberOfPeriods =3,
+                Rows = new List<DimensionColumn>(),
+                SchemaTypeName = SchemaTypeNames.BubbleVisualizationDataSpecType,
+                ShowIndicator = false,
+                Value = new List<MeasureColumn>()
+            };
+
+            // Act
+            var actualJson = sparklineVSDataSpec.ToJsonString();
+            var expectedJObject = JObject.Parse(expectedJson);
+            var actualJObject = JObject.Parse(actualJson);
+
+            // Assert
+            Assert.Equal(expectedJObject, actualJObject);
+        }
+    }
+}