diff --git a/configure b/configure
index 677e19e26db..529b416472b 100755
--- a/configure
+++ b/configure
@@ -20648,6 +20648,7 @@ wine_fn_config_makefile dlls/dpvoice/tests enable_tests
 wine_fn_config_makefile dlls/dpwsockx enable_dpwsockx
 wine_fn_config_makefile dlls/drmclien enable_drmclien
 wine_fn_config_makefile dlls/dsdmo enable_dsdmo
+wine_fn_config_makefile dlls/dsdmo/tests enable_tests
 wine_fn_config_makefile dlls/dsound enable_dsound
 wine_fn_config_makefile dlls/dsound/tests enable_tests
 wine_fn_config_makefile dlls/dsquery enable_dsquery
diff --git a/configure.ac b/configure.ac
index e82ed889545..f2d0c9cd268 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3245,6 +3245,7 @@ WINE_CONFIG_MAKEFILE(dlls/dpvoice/tests)
 WINE_CONFIG_MAKEFILE(dlls/dpwsockx)
 WINE_CONFIG_MAKEFILE(dlls/drmclien)
 WINE_CONFIG_MAKEFILE(dlls/dsdmo)
+WINE_CONFIG_MAKEFILE(dlls/dsdmo/tests)
 WINE_CONFIG_MAKEFILE(dlls/dsound)
 WINE_CONFIG_MAKEFILE(dlls/dsound/tests)
 WINE_CONFIG_MAKEFILE(dlls/dsquery)
diff --git a/dlls/dsdmo/tests/Makefile.in b/dlls/dsdmo/tests/Makefile.in
new file mode 100644
index 00000000000..67378635f3c
--- /dev/null
+++ b/dlls/dsdmo/tests/Makefile.in
@@ -0,0 +1,5 @@
+TESTDLL   = dsdmo.dll
+IMPORTS   = dmoguids uuid msdmo ole32
+
+C_SRCS = \
+	dsdmo.c
diff --git a/dlls/dsdmo/tests/dsdmo.c b/dlls/dsdmo/tests/dsdmo.c
new file mode 100644
index 00000000000..244747a6899
--- /dev/null
+++ b/dlls/dsdmo/tests/dsdmo.c
@@ -0,0 +1,162 @@
+/*
+ * Copyright 2020 Zebediah Figura
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
+ */
+
+#define COBJMACROS
+#include "windef.h"
+#include "wingdi.h"
+#include "mmreg.h"
+#include "mmsystem.h"
+#include "dmo.h"
+#include "initguid.h"
+#include "dsound.h"
+#include "uuids.h"
+#include "wine/test.h"
+
+static const GUID test_iid = {0x33333333};
+static LONG outer_ref = 1;
+
+static ULONG get_refcount(void *iface)
+{
+    IUnknown *unknown = iface;
+    IUnknown_AddRef(unknown);
+    return IUnknown_Release(unknown);
+}
+
+static HRESULT WINAPI outer_QueryInterface(IUnknown *iface, REFIID iid, void **out)
+{
+    if (IsEqualGUID(iid, &IID_IUnknown)
+            || IsEqualGUID(iid, &IID_IMediaObject)
+            || IsEqualGUID(iid, &test_iid))
+    {
+        *out = (IUnknown *)0xdeadbeef;
+        return S_OK;
+    }
+    ok(0, "unexpected call %s\n", wine_dbgstr_guid(iid));
+    return E_NOINTERFACE;
+}
+
+static ULONG WINAPI outer_AddRef(IUnknown *iface)
+{
+    return InterlockedIncrement(&outer_ref);
+}
+
+static ULONG WINAPI outer_Release(IUnknown *iface)
+{
+    return InterlockedDecrement(&outer_ref);
+}
+
+static const IUnknownVtbl outer_vtbl =
+{
+    outer_QueryInterface,
+    outer_AddRef,
+    outer_Release,
+};
+
+static IUnknown test_outer = {&outer_vtbl};
+
+static void test_aggregation(const GUID *clsid)
+{
+    IMediaObject *dmo, *dmo2;
+    IUnknown *unk, *unk2;
+    HRESULT hr;
+    ULONG ref;
+
+    dmo = (IMediaObject *)0xdeadbeef;
+    hr = CoCreateInstance(clsid, &test_outer, CLSCTX_INPROC_SERVER,
+            &IID_IMediaObject, (void **)&dmo);
+    todo_wine ok(hr == E_NOINTERFACE, "Got hr %#x.\n", hr);
+    if (hr != E_NOINTERFACE)
+        return;
+    ok(!dmo, "Got interface %p.\n", dmo);
+
+    hr = CoCreateInstance(clsid, &test_outer, CLSCTX_INPROC_SERVER,
+            &IID_IUnknown, (void **)&unk);
+    ok(hr == S_OK, "Got hr %#x.\n", hr);
+    ok(outer_ref == 1, "Got unexpected refcount %d.\n", outer_ref);
+    ok(unk != &test_outer, "Returned IUnknown should not be outer IUnknown.\n");
+    ref = get_refcount(unk);
+    ok(ref == 1, "Got unexpected refcount %d.\n", ref);
+
+    ref = IUnknown_AddRef(unk);
+    ok(ref == 2, "Got unexpected refcount %d.\n", ref);
+    ok(outer_ref == 1, "Got unexpected refcount %d.\n", outer_ref);
+
+    ref = IUnknown_Release(unk);
+    ok(ref == 1, "Got unexpected refcount %d.\n", ref);
+    ok(outer_ref == 1, "Got unexpected refcount %d.\n", outer_ref);
+
+    hr = IUnknown_QueryInterface(unk, &IID_IUnknown, (void **)&unk2);
+    ok(hr == S_OK, "Got hr %#x.\n", hr);
+    ok(unk2 == unk, "Got unexpected IUnknown %p.\n", unk2);
+    IUnknown_Release(unk2);
+
+    hr = IUnknown_QueryInterface(unk, &IID_IMediaObject, (void **)&dmo);
+    ok(hr == S_OK, "Got hr %#x.\n", hr);
+
+    hr = IMediaObject_QueryInterface(dmo, &IID_IUnknown, (void **)&unk2);
+    ok(hr == S_OK, "Got hr %#x.\n", hr);
+    ok(unk2 == (IUnknown *)0xdeadbeef, "Got unexpected IUnknown %p.\n", unk2);
+
+    hr = IMediaObject_QueryInterface(dmo, &IID_IMediaObject, (void **)&dmo2);
+    ok(hr == S_OK, "Got hr %#x.\n", hr);
+    ok(dmo2 == (IMediaObject *)0xdeadbeef, "Got unexpected IMediaObject %p.\n", dmo2);
+
+    hr = IUnknown_QueryInterface(unk, &test_iid, (void **)&unk2);
+    ok(hr == E_NOINTERFACE, "Got hr %#x.\n", hr);
+    ok(!unk2, "Got unexpected IUnknown %p.\n", unk2);
+
+    hr = IMediaObject_QueryInterface(dmo, &test_iid, (void **)&unk2);
+    ok(hr == S_OK, "Got hr %#x.\n", hr);
+    ok(unk2 == (IUnknown *)0xdeadbeef, "Got unexpected IUnknown %p.\n", unk2);
+
+    IMediaObject_Release(dmo);
+    ref = IUnknown_Release(unk);
+    ok(!ref, "Got unexpected refcount %d.\n", ref);
+    ok(outer_ref == 1, "Got unexpected refcount %d.\n", outer_ref);
+}
+
+START_TEST(dsdmo)
+{
+    static const struct
+    {
+        const GUID *clsid;
+        const GUID *iid;
+    }
+    tests[] =
+    {
+        {&GUID_DSFX_STANDARD_CHORUS,        &IID_IDirectSoundFXChorus},
+        {&GUID_DSFX_STANDARD_COMPRESSOR,    &IID_IDirectSoundFXCompressor},
+        {&GUID_DSFX_STANDARD_DISTORTION,    &IID_IDirectSoundFXDistortion},
+        {&GUID_DSFX_STANDARD_ECHO,          &IID_IDirectSoundFXEcho},
+        {&GUID_DSFX_STANDARD_FLANGER,       &IID_IDirectSoundFXFlanger},
+        {&GUID_DSFX_STANDARD_GARGLE,        &IID_IDirectSoundFXGargle},
+        {&GUID_DSFX_STANDARD_I3DL2REVERB,   &IID_IDirectSoundFXI3DL2Reverb},
+        {&GUID_DSFX_STANDARD_PARAMEQ,       &IID_IDirectSoundFXParamEq},
+        {&GUID_DSFX_WAVES_REVERB,           &IID_IDirectSoundFXWavesReverb},
+    };
+    unsigned int i;
+
+    CoInitializeEx(NULL, COINIT_MULTITHREADED);
+
+    for (i = 0; i < ARRAY_SIZE(tests); ++i)
+    {
+        test_aggregation(tests[i].clsid);
+    }
+
+    CoUninitialize();
+}