add NamedLocks tests for zk2

go/test/endtoend/topotest/zk2/main_test.go

@@ -19,6 +19,7 @@ package zk2
 import (
 	"context"
 	"flag"
+	"fmt"
 	"os"
 	"testing"
 	"time"
@@ -197,6 +198,53 @@ func TestKeyspaceLocking(t *testing.T) {
 	topoutils.WaitForBoolValue(t, &secondThreadLockAcquired, true)
 }
 
+// TestNamedLocking tests that named locking works as intended.
+func TestNamedLocking(t *testing.T) {
+	// Create topo server connection.
+	ts, err := topo.OpenServer(*clusterInstance.TopoFlavorString(), clusterInstance.VtctldClientProcess.TopoGlobalAddress, clusterInstance.VtctldClientProcess.TopoGlobalRoot)
+	require.NoError(t, err)
+
+	ctx := context.Background()
+	lockName := "TestNamedLocking"
+	action := "Testing"
+
+	// Acquire a named lock.
+	ctx, unlock, err := ts.LockName(ctx, lockName, action)
+	require.NoError(t, err)
+
+	// Check that we can't reacquire it from the same context.
+	_, _, err = ts.LockName(ctx, lockName, action)
+	require.ErrorContains(t, err, fmt.Sprintf("lock for named %s is already held", lockName))
+
+	// Check that CheckNameLocked doesn't return an error as we should still be
+	// holding the lock.
+	err = topo.CheckNameLocked(ctx, lockName)
+	require.NoError(t, err)
+
+	// We'll now try to acquire the lock from a different goroutine.
+	secondCallerAcquired := false
+	go func() {
+		_, unlock, err := ts.LockName(context.Background(), lockName, action)
+		defer unlock(&err)
+		require.NoError(t, err)
+		secondCallerAcquired = true
+	}()
+
+	// Wait for some time and ensure that the second attempt at acquiring the lock
+	// is blocked.
+	time.Sleep(100 * time.Millisecond)
+	require.False(t, secondCallerAcquired)
+
+	// Unlock the name.
+	unlock(&err)
+	// Check that we no longer have the named lock.
+	err = topo.CheckNameLocked(ctx, lockName)
+	require.ErrorContains(t, err, fmt.Sprintf("named %s is not locked (no lockInfo in map)", lockName))
+
+	// Wait to see that the second goroutine WAS now able to acquire the named lock.
+	topoutils.WaitForBoolValue(t, &secondCallerAcquired, true)
+}
+
 func execMulti(t *testing.T, conn *mysql.Conn, query string) []*sqltypes.Result {
 	t.Helper()
 	var res []*sqltypes.Result