diff --git a/server/modules/filter/dbfwfilter/test/maxscale/mock/dcb.hh b/server/modules/filter/dbfwfilter/test/maxscale/mock/dcb.hh
new file mode 100644
index 000000000..5834d0463
--- /dev/null
+++ b/server/modules/filter/dbfwfilter/test/maxscale/mock/dcb.hh
@@ -0,0 +1,53 @@
+#pragma once
+/*
+ * Copyright (c) 2016 MariaDB Corporation Ab
+ *
+ * Use of this software is governed by the Business Source License included
+ * in the LICENSE.TXT file and at www.mariadb.com/bsl11.
+ *
+ * Change Date: 2020-01-01
+ *
+ * On the date above, in accordance with the Business Source License, use
+ * of this software will be governed by version 2 or later of the General
+ * Public License.
+ */
+
+#include "mock.hh"
+#include <maxscale/dcb.h>
+#include <maxscale/session.h>
+
+namespace maxscale
+{
+
+namespace mock
+{
+
+/**
+ * The class Dcb provides a mock DCB that can be used when testing.
+ */
+class Dcb : public DCB
+{
+    Dcb(const Dcb&);
+    Dcb& operator = (const Dcb&);
+
+public:
+    /**
+     * Constructor
+     *
+     * @param pSession  The session object of the DCB.
+     * @param zUser     The client of the connection.
+     * @param zHost     The host of the connection.
+     */
+    Dcb(MXS_SESSION* pSession,
+        const char* zUser,
+        const char* zHost);
+    ~Dcb();
+
+private:
+    std::string m_user;
+    std::string m_host;
+};
+
+}
+
+}
diff --git a/server/modules/filter/dbfwfilter/test/maxscale/mock/session.hh b/server/modules/filter/dbfwfilter/test/maxscale/mock/session.hh
new file mode 100644
index 000000000..ea622505b
--- /dev/null
+++ b/server/modules/filter/dbfwfilter/test/maxscale/mock/session.hh
@@ -0,0 +1,51 @@
+#pragma once
+/*
+ * Copyright (c) 2016 MariaDB Corporation Ab
+ *
+ * Use of this software is governed by the Business Source License included
+ * in the LICENSE.TXT file and at www.mariadb.com/bsl11.
+ *
+ * Change Date: 2020-01-01
+ *
+ * On the date above, in accordance with the Business Source License, use
+ * of this software will be governed by version 2 or later of the General
+ * Public License.
+ */
+
+#include "mock.hh"
+#include <maxscale/session.h>
+#include "dcb.hh"
+
+namespace maxscale
+{
+
+namespace mock
+{
+
+/**
+ * The class Session provides a mock MXS_SESSION that can be used when
+ * testing.
+ */
+class Session : public MXS_SESSION
+{
+    Session(const Session&);
+    Session& operator = (Session&);
+
+public:
+    /**
+     * Constructor
+     *
+     * @param zUser  The client of the session,
+     * @param zHost  The host of the client.
+     */
+    Session(const char* zUser,
+            const char* zHost = "127.0.0.1");
+    ~Session();
+
+private:
+    Dcb m_client_dcb;
+};
+
+}
+
+}
diff --git a/server/modules/filter/dbfwfilter/test/mock_dcb.cc b/server/modules/filter/dbfwfilter/test/mock_dcb.cc
new file mode 100644
index 000000000..9d561ae58
--- /dev/null
+++ b/server/modules/filter/dbfwfilter/test/mock_dcb.cc
@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2016 MariaDB Corporation Ab
+ *
+ * Use of this software is governed by the Business Source License included
+ * in the LICENSE.TXT file and at www.mariadb.com/bsl11.
+ *
+ * Change Date: 2020-01-01
+ *
+ * On the date above, in accordance with the Business Source License, use
+ * of this software will be governed by version 2 or later of the General
+ * Public License.
+ */
+
+#include "maxscale/mock/dcb.hh"
+
+namespace
+{
+
+void initialize_dcb(DCB* pDcb)
+{
+    memset(pDcb, 0, sizeof(DCB));
+
+    pDcb->dcb_chk_top = CHK_NUM_DCB;
+    pDcb->fd = DCBFD_CLOSED;
+    pDcb->state = DCB_STATE_ALLOC;
+    pDcb->ssl_state = SSL_HANDSHAKE_UNKNOWN;
+    pDcb->dcb_chk_tail = CHK_NUM_DCB;
+}
+
+}
+
+namespace maxscale
+{
+
+namespace mock
+{
+
+Dcb::Dcb(MXS_SESSION* pSession,
+         const char* zUser,
+         const char* zHost)
+    : m_user(zUser)
+    , m_host(zHost)
+{
+    DCB* pDcb = this;
+    initialize_dcb(this);
+
+    pDcb->session = pSession;
+    pDcb->remote = const_cast<char*>(zHost);
+    pDcb->user = const_cast<char*>(zUser);
+}
+
+Dcb::~Dcb()
+{
+}
+
+}
+
+}
diff --git a/server/modules/filter/dbfwfilter/test/mock_session.cc b/server/modules/filter/dbfwfilter/test/mock_session.cc
new file mode 100644
index 000000000..7d14439d7
--- /dev/null
+++ b/server/modules/filter/dbfwfilter/test/mock_session.cc
@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2016 MariaDB Corporation Ab
+ *
+ * Use of this software is governed by the Business Source License included
+ * in the LICENSE.TXT file and at www.mariadb.com/bsl11.
+ *
+ * Change Date: 2020-01-01
+ *
+ * On the date above, in accordance with the Business Source License, use
+ * of this software will be governed by version 2 or later of the General
+ * Public License.
+ */
+
+#include "maxscale/mock/session.hh"
+
+namespace maxscale
+{
+
+namespace mock
+{
+
+Session::Session(const char* zUser,
+                 const char* zHost)
+    : m_client_dcb(this, zUser, zHost)
+{
+    MXS_SESSION* pSession = this;
+
+    memset(pSession, 0, sizeof(MXS_SESSION));
+
+    pSession->ses_chk_top = CHK_NUM_SESSION;
+    pSession->state = SESSION_STATE_ALLOC;
+    pSession->ses_chk_tail = CHK_NUM_SESSION;
+
+    pSession->client_dcb = &m_client_dcb;
+}
+
+Session::~Session()
+{
+}
+
+}
+
+}