Adding EditCell constructor validation (#301)

* New unit tests!
* New CopyTo method!
* New null validation!

YEAH!!!

src/Microsoft.SqlTools.ServiceLayer/EditData/Contracts/EditCell.cs

@@ -4,6 +4,7 @@
 //
 
 using Microsoft.SqlTools.ServiceLayer.QueryExecution.Contracts;
+using Microsoft.SqlTools.Utility;
 
 namespace Microsoft.SqlTools.ServiceLayer.EditData.Contracts
 {
@@ -24,11 +25,10 @@ namespace Microsoft.SqlTools.ServiceLayer.EditData.Contracts
         /// <param name="isDirty">Whether or not the edit cell is dirty</param>
         public EditCell(DbCellValue dbCellValue, bool isDirty)
         {
-            IsDirty = isDirty;
+            Validate.IsNotNull(nameof(dbCellValue), dbCellValue);
+            dbCellValue.CopyTo(this);
 
-            DisplayValue = dbCellValue.DisplayValue;
-            IsNull = dbCellValue.IsNull;
-            RawObject = dbCellValue.RawObject;
+            IsDirty = isDirty;
         }
 
         /// <summary>

src/Microsoft.SqlTools.ServiceLayer/QueryExecution/Contracts/DbCellValue.cs

@@ -3,6 +3,8 @@
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 //
 
+using Microsoft.SqlTools.Utility;
+
 namespace Microsoft.SqlTools.ServiceLayer.QueryExecution.Contracts
 {
     /// <summary>
@@ -24,5 +26,18 @@ namespace Microsoft.SqlTools.ServiceLayer.QueryExecution.Contracts
         /// The raw object for the cell, for use internally
         /// </summary>
         internal object RawObject { get; set; }
+
+        /// <summary>
+        /// Copies the values of this DbCellValue into another DbCellValue (or child object)
+        /// </summary>
+        /// <param name="other">The DbCellValue (or child) that will receive the values</param>
+        public virtual void CopyTo(DbCellValue other)
+        {
+            Validate.IsNotNull(nameof(other), other);
+
+            other.DisplayValue = DisplayValue;
+            other.IsNull = IsNull;
+            other.RawObject = RawObject;
+        }
     }
 }

test/Microsoft.SqlTools.ServiceLayer.UnitTests/EditData/EditCellTests.cs

@@ -0,0 +1,47 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using System;
+using Microsoft.SqlTools.ServiceLayer.EditData.Contracts;
+using Microsoft.SqlTools.ServiceLayer.QueryExecution.Contracts;
+using Xunit;
+
+namespace Microsoft.SqlTools.ServiceLayer.UnitTests.EditData
+{
+    public class EditCellTests
+    {
+        [Fact]
+        public void ConstructNullDbCell()
+        {
+            // If: I construct an EditCell with a null DbCellValue
+            // Then: It should throw
+            Assert.Throws<ArgumentNullException>(() => new EditCell(null, true));
+        }
+
+        [Fact]
+        public void ConstructValid()
+        {
+            // Setup: Create a DbCellValue to copy the values from
+            DbCellValue source = new DbCellValue
+            {
+                DisplayValue = "qqq",
+                IsNull = true,
+                RawObject = 12
+            };
+
+            // If: I construct an EditCell with a valid DbCellValue
+            EditCell ec = new EditCell(source, true);
+
+            // Then:
+            // ... The values I provided in the DbCellValue should be present
+            Assert.Equal(source.DisplayValue, ec.DisplayValue);
+            Assert.Equal(source.IsNull, ec.IsNull);
+            Assert.Equal(source.RawObject, ec.RawObject);
+
+            // ... The is dirty value I set should be present
+            Assert.True(ec.IsDirty);
+        }
+    }
+}

test/Microsoft.SqlTools.ServiceLayer.UnitTests/QueryExecution/DbCellValueTests.cs

@@ -0,0 +1,53 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using System;
+using Microsoft.SqlTools.ServiceLayer.QueryExecution.Contracts;
+using Xunit;
+
+namespace Microsoft.SqlTools.ServiceLayer.UnitTests.QueryExecution
+{
+    public class DbCellValueTests
+    {
+        [Fact]
+        public void ConstructValid()
+        {
+            // If: I construct a new DbCellValue
+            DbCellValue dbc = new DbCellValue
+            {
+                DisplayValue = "qqq",
+                IsNull = true,
+                RawObject = 12
+            };
+
+            // Then: It should have the values I specified in it
+            Assert.Equal("qqq", dbc.DisplayValue);
+            Assert.Equal(12, dbc.RawObject);
+            Assert.True(dbc.IsNull);
+        }
+
+        [Fact]
+        public void CopyToNullOther()
+        {
+            // If: I copy a DbCellValue to null
+            // Then: I should get an exception
+            Assert.Throws<ArgumentNullException>(() => new DbCellValue().CopyTo(null));
+        }
+
+        [Fact]
+        public void CopyToValid()
+        {
+            // If: I copy a DbCellValue to another DbCellValue
+            DbCellValue source = new DbCellValue {DisplayValue = "qqq", IsNull = true, RawObject = 12};
+            DbCellValue dest = new DbCellValue();
+            source.CopyTo(dest);
+
+            // Then: The source values should be in the dest
+            Assert.Equal(source.DisplayValue, dest.DisplayValue);
+            Assert.Equal(source.IsNull, dest.IsNull);
+            Assert.Equal(source.RawObject, dest.RawObject);
+        }
+    }
+}