Add high-level summary to cryptographic fixtures

Author: edwardneal

src/Microsoft.Data.SqlClient/tests/Common/Fixtures/AzureKeyVaultKeyFixtureBase.cs

@@ -9,6 +9,14 @@
 
 namespace Microsoft.Data.SqlClient.Tests.Common.Fixtures;
 
+/// <summary>
+/// Provides a base class for managing Azure Key Vault keys in test fixtures.
+/// </summary>
+/// <remarks>
+/// This class simplifies the creation and cleanup of RSA keys in an Azure Key Vault during testing
+/// scenarios. It ensures that any keys created during the fixture's lifetime are properly deleted when the fixture is
+/// disposed.
+/// </remarks>
 public abstract class AzureKeyVaultKeyFixtureBase : IDisposable
 {
     private readonly KeyClient _keyClient;

src/Microsoft.Data.SqlClient/tests/Common/Fixtures/CertificateFixtureBase.cs

@@ -12,6 +12,19 @@
 
 namespace Microsoft.Data.SqlClient.Tests.Common.Fixtures;
 
+/// <summary>
+/// Provides a base class for managing the creation, storage, and disposal of X.509 certificates used in cryptographic
+/// operations. This class is designed to facilitate scenarios where certificates need to be programmatically generated,
+/// added to certificate stores, and cleaned up after use.
+/// </summary>
+/// <remarks>
+/// This class includes functionality for creating self-signed certificates with specific configurations,
+/// adding certificates to system certificate stores, and ensuring proper cleanup of certificates to avoid resource
+/// leaks. It is intended to be used as a base class for test fixtures or other scenarios requiring temporary
+/// certificate management.
+/// <para>The class implements <see cref="IDisposable"/> to ensure that any certificates added to
+/// certificate stores are removed and properly disposed of when the object is no longer needed.</para>
+/// </remarks>
 public abstract class CertificateFixtureBase : IDisposable
 {
     /// <summary>

src/Microsoft.Data.SqlClient/tests/Common/Fixtures/ColumnEncryptionCertificateFixture.cs

@@ -8,6 +8,14 @@
 
 namespace Microsoft.Data.SqlClient.Tests.Common.Fixtures;
 
+/// <summary>
+/// Provides a fixture for managing certificates used in column encryption scenarios.
+/// </summary>
+/// <remarks>
+/// This class creates and manages certificates for testing or operational purposes, including primary
+/// and secondary column encryption certificates, as well as a certificate without a private key. Certificates are
+/// added to the appropriate certificate stores based on the current user's permissions.
+/// </remarks>
 public sealed class ColumnEncryptionCertificateFixture : CertificateFixtureBase
 {
     public X509Certificate2 PrimaryColumnEncryptionCertificate { get; }

src/Microsoft.Data.SqlClient/tests/Common/Fixtures/ColumnMasterKeyCertificateFixture.cs

@@ -7,6 +7,13 @@
 
 namespace Microsoft.Data.SqlClient.Tests.Common.Fixtures;
 
+/// <summary>
+/// Provides a test fixture for managing a column master key certificate.
+/// </summary>
+/// <remarks>
+/// This class is intended to simplify the setup and teardown of a column master key certificate for
+/// testing purposes. It creates and optionally adds the certificate to the specified certificate store.
+/// </remarks>
 public class ColumnMasterKeyCertificateFixture : CertificateFixtureBase
 {
     public ColumnMasterKeyCertificateFixture()

src/Microsoft.Data.SqlClient/tests/Common/Fixtures/CspCertificateFixture.cs

@@ -8,6 +8,14 @@
 
 namespace Microsoft.Data.SqlClient.Tests.Common.Fixtures;
 
+/// <summary>
+/// Provides a fixture for working with certificates backed by a Cryptographic Service Provider (CSP).
+/// </summary>
+/// <remarks>
+/// This class creates and manages a certificate stored in the current user's certificate store,  along
+/// with its associated CSP key path. It is intended to facilitate testing or scenarios  requiring temporary
+/// certificates.
+/// </remarks>
 public class CspCertificateFixture : CertificateFixtureBase
 {
     public CspCertificateFixture()