quartz/tests: Test querying IFilterMapper2 from FilterGraph.

dlls/quartz/tests/filtermapper.c

@@ -286,12 +286,70 @@ static void test_legacy_filter_registration(void)
     if (pMapper2) IFilterMapper2_Release(pMapper2);
 }
 
+static ULONG getRefcount(IUnknown *iface)
+{
+    IUnknown_AddRef(iface);
+    return IUnknown_Release(iface);
+}
+
+static void test_ifiltermapper_from_filtergraph(void)
+{
+    IFilterGraph2* pgraph2 = NULL;
+    IFilterMapper2 *pMapper2 = NULL;
+    IFilterGraph *filtergraph = NULL;
+    HRESULT hr;
+    ULONG refcount;
+
+    hr = CoCreateInstance(&CLSID_FilterGraph, NULL, CLSCTX_INPROC_SERVER, &IID_IFilterGraph2, (LPVOID*)&pgraph2);
+    ok(hr == S_OK, "CoCreateInstance failed with %08x\n", hr);
+    if (!pgraph2) goto out;
+
+    hr = IFilterGraph2_QueryInterface(pgraph2, &IID_IFilterMapper2, (LPVOID*)&pMapper2);
+    ok(hr == S_OK, "IFilterGraph2_QueryInterface failed with %08x\n", hr);
+    if (!pMapper2) goto out;
+
+    refcount = getRefcount((IUnknown*)pgraph2);
+    ok(refcount == 2, "unexpected reference count: %u\n", refcount);
+    refcount = getRefcount((IUnknown*)pMapper2);
+    ok(refcount == 2, "unexpected reference count: %u\n", refcount);
+
+    IFilterMapper2_AddRef(pMapper2);
+    refcount = getRefcount((IUnknown*)pgraph2);
+    ok(refcount == 3, "unexpected reference count: %u\n", refcount);
+    refcount = getRefcount((IUnknown*)pMapper2);
+    ok(refcount == 3, "unexpected reference count: %u\n", refcount);
+    IFilterMapper2_Release(pMapper2);
+
+    hr = IFilterMapper2_QueryInterface(pMapper2, &IID_IFilterGraph, (LPVOID*)&filtergraph);
+    ok(hr == S_OK, "IFilterMapper2_QueryInterface failed with %08x\n", hr);
+    if (!filtergraph) goto out;
+
+    IFilterMapper2_Release(pMapper2);
+    pMapper2 = NULL;
+    IFilterGraph_Release(filtergraph);
+    filtergraph = NULL;
+
+    hr = CoCreateInstance(&CLSID_FilterMapper2, NULL, CLSCTX_INPROC_SERVER, &IID_IFilterMapper2, (LPVOID*)&pMapper2);
+    ok(hr == S_OK, "CoCreateInstance failed with %08x\n", hr);
+    if (!pMapper2) goto out;
+
+    hr = IFilterMapper2_QueryInterface(pMapper2, &IID_IFilterGraph, (LPVOID*)&filtergraph);
+    ok(hr == E_NOINTERFACE, "IFilterMapper2_QueryInterface unexpected result: %08x\n", hr);
+
+    out:
+
+    if (pMapper2) IFilterMapper2_Release(pMapper2);
+    if (filtergraph) IFilterGraph_Release(filtergraph);
+    if (pgraph2) IFilterGraph2_Release(pgraph2);
+}
+
 START_TEST(filtermapper)
 {
     CoInitialize(NULL);
 
     test_fm2_enummatchingfilters();
     test_legacy_filter_registration();
+    test_ifiltermapper_from_filtergraph();
 
     CoUninitialize();
 }