Test | Convert DateTimeVariantTests to xunit (#4196)

Author: mdaigle

.github/instructions/testing.instructions.md

@@ -321,6 +321,38 @@ Extended assertions for SqlClient:
 AssertExtensions.ThrowsContains<SqlException>(() => action(), "expected message");
 ```
 
+### RAII Database Object Classes
+When writing manual integration tests that require transient database objects, use the RAII classes from `Microsoft.Data.SqlClient.Tests.Common.Fixtures.DatabaseObjects` instead of manually writing `try/finally` blocks with DDL `DROP`/`CREATE` statements.
+
+**Available classes:**
+
+| Class | SQL generated | Example definition argument |
+|-------|--------------|----------------------------|
+| `Table` | `CREATE TABLE {Name} {definition}` | `"(Id INT, Value NVARCHAR(100))"` |
+| `StoredProcedure` | `CREATE PROCEDURE {Name} {definition}` | `"AS BEGIN SELECT 1 END"` |
+| `UserDefinedType` | `CREATE TYPE [dbo].{Name} AS {definition}` | `"TABLE (f1 INT)"` |
+
+Each class generates a unique object name from the given prefix (incorporating a timestamp-based GUID, username, and machine name), creates the object on construction (requiring the connection to already be open), and drops it when disposed. The generated name is available via the `.Name` property.
+
+**Pattern:**
+```csharp
+using SqlConnection conn = new(DataTestUtility.TCPConnectionString);
+conn.Open();
+
+using Table testTable = new(conn, "MyTable", "(Id INT, Name NVARCHAR(100))");
+using StoredProcedure proc = new(conn, "MyProc", $"AS BEGIN SELECT * FROM {testTable.Name} END");
+
+using SqlCommand cmd = conn.CreateCommand();
+cmd.CommandText = proc.Name;
+cmd.CommandType = CommandType.StoredProcedure;
+// ... objects are automatically dropped when the scope ends
+```
+
+**Rules:**
+- Open the connection **before** constructing any database object (the constructor executes DDL immediately)
+- When objects depend on each other (e.g., a stored procedure that references a table), declare the dependent object **last** so it is disposed first — `using` declarations are disposed in reverse order
+- Use the `.Name` property directly wherever you need to reference the object in SQL; for `UserDefinedType` this already includes the `[dbo].` schema prefix, making it suitable for use as a TVP `TypeName`
+
 ## Code Coverage
 
 ### Running with Coverage

src/Microsoft.Data.SqlClient/tests/Common/DisposableArray.cs

@@ -60,16 +60,32 @@ public T this[int i]
 
         /// <summary>
         /// Disposes all elements in the current instance. Each element will be checked for
-        /// <c>null</c> before disposing it.
+        /// <c>null</c> before disposing it. All elements are disposed even if earlier disposals
+        /// throw; any exceptions are collected and rethrown as an <see cref="AggregateException"/>
+        /// after all elements have been attempted.
         /// </summary>
         public void Dispose()
         {
+            List<Exception>? exceptions = null;
+
             foreach (T element in _elements)
             {
-                element?.Dispose();
+                try
+                {
+                    element?.Dispose();
+                }
+                catch (Exception ex)
+                {
+                    (exceptions ??= new List<Exception>()).Add(ex);
+                }
             }
 
             GC.SuppressFinalize(this);
+
+            if (exceptions is not null)
+            {
+                throw new AggregateException(exceptions);
+            }
         }
 
         /// <inheritdoc/>

src/Microsoft.Data.SqlClient/tests/ManualTests/Microsoft.Data.SqlClient.ManualTests.csproj

@@ -206,7 +206,6 @@
     <Compile Include="SQL\MARSTest\MARSTest.cs" />
     <Compile Include="SQL\MirroringTest\ConnectionOnMirroringTest.cs" />
     <Compile Include="SQL\ParallelTransactionsTest\ParallelTransactionsTest.cs" />
-    <Compile Include="SQL\ParameterTest\DateTimeVariantTest.cs" />
     <Compile Include="SQL\ParameterTest\ParametersTest.cs" />
     <Compile Include="SQL\ParameterTest\SqlAdapterUpdateBatch.cs" />
     <Compile Include="SQL\ParameterTest\SteAttribute.cs" />
@@ -262,10 +261,6 @@
              CopyToOutputDirectory="PreserveNewest" />
 
     <!-- Baseline files for individual test groups -->
-    <Content Include="SQL\ParameterTest\DateTimeVariant.bsl">
-      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
-      <Link>DateTimeVariant.bsl</Link>
-    </Content>
     <Content Include="SQL\ParameterTest\StreamInputParameter_DebugMode.bsl">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
       <Link>StreamInputParameter_DebugMode.bsl</Link>