Test for absence of metrics from connections without pools.

Refactor tests to take string arguments rather than being parameterized with objects. This makes it easier to view/run the tests in Tests Explorer.

Author: bgrainger

tests/MySqlConnector.Tests/Metrics/ConnectionsUsageTests.cs

@@ -5,10 +5,12 @@ namespace MySqlConnector.Tests.Metrics;
 public class ConnectionsUsageTests : MetricsTestsBase
 {
     [Theory(Skip = MetricsSkip)]
-	[MemberData(nameof(GetPoolCreators))]
-	public void PoolCreators(IConnectionCreator connectionCreator)
+	[InlineData("DataSource|true|")]
+	[InlineData("DataSource|true|metrics-test")]
+	[InlineData("Plain|true")]
+	public void ConnectionsWithPoolsHaveMetrics(string connectionCreatorSpec)
     {
-		connectionCreator.SetConnectionStringBuilder(CreateConnectionStringBuilder());
+		using var connectionCreator = CreateConnectionCreator(connectionCreatorSpec, CreateConnectionStringBuilder());
 		PoolName = connectionCreator.PoolName;
 
 		// no connections at beginning of test
@@ -55,15 +57,44 @@ public void PoolCreators(IConnectionCreator connectionCreator)
 		AssertMeasurement("db.client.connections.usage|idle", 2);
 		AssertMeasurement("db.client.connections.usage|used", 0);
 		Assert.Equal(2, Server.ActiveConnections);
-
-		connectionCreator.Dispose();
 	}
 
-	public static IEnumerable<object[]> GetPoolCreators()
+	[Theory(Skip = MetricsSkip)]
+    [InlineData("DataSource|false|")]
+    [InlineData("DataSource|false|metrics-test")]
+    [InlineData("Plain|false")]
+    public void ConnectionsWithoutPoolsHaveNoMetrics(string connectionCreatorSpec)
 	{
-		yield return new object[] { new DataSourceConnectionCreator("metrics-test") };
-		yield return new object[] { new DataSourceConnectionCreator(null) };
-		yield return new object[] { new PlainConnectionCreator() };
+		using var connectionCreator = CreateConnectionCreator(connectionCreatorSpec, CreateConnectionStringBuilder());
+		PoolName = connectionCreator.PoolName;
+
+		// no connections at beginning of test
+		AssertMeasurement("db.client.connections.usage", 0);
+		AssertMeasurement("db.client.connections.usage|idle", 0);
+		AssertMeasurement("db.client.connections.usage|used", 0);
+		Assert.Equal(0, Server.ActiveConnections);
+
+		// opening a connection doesn't change connection counts
+		using (var connection = connectionCreator.OpenConnection())
+		{
+			AssertMeasurement("db.client.connections.usage", 0);
+			AssertMeasurement("db.client.connections.usage|idle", 0);
+			AssertMeasurement("db.client.connections.usage|used", 0);
+			Assert.Equal(1, Server.ActiveConnections);
+		}
+
+		// closing it doesn't create an idle connection but closes it immediately
+		AssertMeasurement("db.client.connections.usage", 0);
+		AssertMeasurement("db.client.connections.usage|idle", 0);
+		AssertMeasurement("db.client.connections.usage|used", 0);
+
+		// disposing the connection sends a COM_QUIT packet and immediately returns; give the in-proc server a chance to process it
+		for (var retry = 0; retry < 20; retry++)
+		{
+			if (Server.ActiveConnections != 0)
+				Thread.Sleep(1);
+		}
+		Assert.Equal(0, Server.ActiveConnections);
 	}
 
 	[Fact(Skip = MetricsSkip)]
@@ -135,4 +166,15 @@ public async Task PendingRequestForOpenFromPool()
 
 		AssertMeasurement("db.client.connections.pending_requests", 0);
 	}
+
+	private IConnectionCreator CreateConnectionCreator(string spec, MySqlConnectionStringBuilder connectionStringBuilder)
+	{
+		var parts = spec.Split('|');
+		return parts[0] switch
+		{
+			"DataSource" => new DataSourceConnectionCreator(bool.Parse(parts[1]), parts[2] == "" ? null : parts[2], connectionStringBuilder),
+			"Plain" => new PlainConnectionCreator(bool.Parse(parts[1]), connectionStringBuilder),
+			_ => throw new NotSupportedException(),
+		};
+	}
 }

tests/MySqlConnector.Tests/Metrics/IConnectionCreator.cs

@@ -4,44 +4,46 @@ namespace MySqlConnector.Tests.Metrics;
 
 public interface IConnectionCreator : IDisposable
 {
-	void SetConnectionStringBuilder(MySqlConnectionStringBuilder connectionStringBuilder);
 	string PoolName { get; }
 	MySqlConnection OpenConnection();
 }
 
-internal sealed class DataSourceConnectionCreator(string? poolName) : IConnectionCreator
+internal sealed class DataSourceConnectionCreator : IConnectionCreator
 {
-	public void SetConnectionStringBuilder(MySqlConnectionStringBuilder connectionStringBuilder)
+	public DataSourceConnectionCreator(bool usePooling, string? poolName, MySqlConnectionStringBuilder connectionStringBuilder)
 	{
-		m_connectionStringBuilder = connectionStringBuilder;
+        connectionStringBuilder.Pooling =	usePooling;
 		m_dataSource = new MySqlDataSourceBuilder(connectionStringBuilder.ConnectionString)
-			.UseName(m_poolName)
+			.UseName(poolName)
 			.Build();
-	}
+        PoolName = poolName ?? connectionStringBuilder!.GetConnectionString(includePassword: false);
+    }
 
-	public MySqlConnection OpenConnection() => m_dataSource!.OpenConnection();
-	public string PoolName => m_poolName ?? m_connectionStringBuilder!.GetConnectionString(includePassword: false);
-	public override string ToString() => $"DataSource: {m_poolName ?? "(unnamed)"}";
+    public MySqlConnection OpenConnection() => m_dataSource!.OpenConnection();
+	public string PoolName { get; }
 	public void Dispose() => m_dataSource!.Dispose();
 
-	private readonly string? m_poolName = poolName;
-	private MySqlConnectionStringBuilder? m_connectionStringBuilder;
-	private MySqlDataSource? m_dataSource;
+	private readonly MySqlDataSource m_dataSource;
 }
 
 internal sealed class PlainConnectionCreator : IConnectionCreator
 {
+	public PlainConnectionCreator(bool usePooling, MySqlConnectionStringBuilder connectionStringBuilder)
+	{
+		connectionStringBuilder.Pooling = usePooling;
+		m_connectionString = connectionStringBuilder.ConnectionString;
+		PoolName = connectionStringBuilder.GetConnectionString(includePassword: false);
+    }
+
 	public MySqlConnection OpenConnection()
 	{
-		var connection = new MySqlConnection(m_connectionStringBuilder!.ConnectionString);
+		var connection = new MySqlConnection(m_connectionString);
 		connection.Open();
 		return connection;
 	}
 
-	public void SetConnectionStringBuilder(MySqlConnectionStringBuilder connectionStringBuilder) => m_connectionStringBuilder = connectionStringBuilder;
-	public string PoolName => m_connectionStringBuilder!.GetConnectionString(includePassword: false);
-	public override string ToString() => "Plain";
+	public string PoolName { get; }
 	public void Dispose() { }
 
-	private MySqlConnectionStringBuilder? m_connectionStringBuilder;
+	private readonly string m_connectionString;
 }