opcua: add FindNamespace and tests to client

client.go

@@ -1084,6 +1084,21 @@ func (c *Client) NamespaceArray() ([]string, error) {
 	return ns, nil
 }
 
+// FindNamespace returns the id of the namespace with the given name.
+func (c *Client) FindNamespace(name string) (uint16, error) {
+	stats.Client().Add("FindNamespace", 1)
+	nsa, err := c.NamespaceArray()
+	if err != nil {
+		return 0, err
+	}
+	for i, ns := range nsa {
+		if ns == name {
+			return uint16(i), nil
+		}
+	}
+	return 0, errors.Errorf("namespace not found. name=%s", name)
+}
+
 // UpdateNamespaces updates the list of cached namespaces from the server.
 func (c *Client) UpdateNamespaces() error {
 	stats.Client().Add("UpdateNamespaces", 1)

uatest/namespace_test.go

@@ -0,0 +1,52 @@
+//go:build integration
+// +build integration
+
+package uatest
+
+import (
+	"context"
+	"testing"
+
+	"github.com/pascaldekloe/goe/verify"
+
+	"github.com/gopcua/opcua"
+)
+
+func TestNamespace(t *testing.T) {
+	srv := NewServer("rw_server.py")
+	defer srv.Close()
+
+	c := opcua.NewClient(srv.Endpoint, srv.Opts...)
+	if err := c.Connect(context.Background()); err != nil {
+		t.Fatal(err)
+	}
+	defer c.Close()
+
+	t.Run("NamespaceArray", func(t *testing.T) {
+		got, err := c.NamespaceArray()
+		if err != nil {
+			t.Fatal(err)
+		}
+		want := []string{
+			"http://opcfoundation.org/UA/",
+			"urn:freeopcua:python:server",
+			"http://gopcua.com/",
+		}
+		verify.Values(t, "", got, want)
+	})
+	t.Run("FindNamespace", func(t *testing.T) {
+		ns, err := c.FindNamespace("http://gopcua.com/")
+		if err != nil {
+			t.Fatal(err)
+		}
+		if got, want := ns, uint16(2); got != want {
+			t.Fatalf("got namespace id %d want %d", got, want)
+		}
+	})
+	t.Run("UpdateNamespaces", func(t *testing.T) {
+		err := c.UpdateNamespaces()
+		if err != nil {
+			t.Fatal(err)
+		}
+	})
+}