scrrun: Implement DriveLetter property for a drive.

dlls/scrrun/filesystem.c

@@ -687,8 +687,17 @@ static HRESULT WINAPI drive_get_Path(IDrive *iface, BSTR *path)
 static HRESULT WINAPI drive_get_DriveLetter(IDrive *iface, BSTR *letter)
 {
     struct drive *This = impl_from_IDrive(iface);
-    FIXME("(%p)->(%p): stub\n", This, letter);
-    return E_NOTIMPL;
+
+    TRACE("(%p)->(%p)\n", This, letter);
+
+    if (!letter)
+        return E_POINTER;
+
+    *letter = SysAllocStringLen(This->root, 1);
+    if (!*letter)
+        return E_OUTOFMEMORY;
+
+    return S_OK;
 }
 
 static HRESULT WINAPI drive_get_ShareName(IDrive *iface, BSTR *share_name)

dlls/scrrun/tests/filesystem.c

@@ -1240,10 +1240,19 @@ static void test_DriveCollection(void)
     while (IEnumVARIANT_Next(enumvar, 1, &var, &fetched) == S_OK) {
         IDrive *drive = (IDrive*)V_DISPATCH(&var);
         DriveTypeConst type;
+        BSTR str;
 
         hr = IDrive_get_DriveType(drive, &type);
         ok(hr == S_OK, "got 0x%08x\n", hr);
 
+        hr = IDrive_get_DriveLetter(drive, NULL);
+        ok(hr == E_POINTER, "got 0x%08x\n", hr);
+
+        hr = IDrive_get_DriveLetter(drive, &str);
+        ok(hr == S_OK, "got 0x%08x\n", hr);
+        ok(SysStringLen(str) == 1, "got string %s\n", wine_dbgstr_w(str));
+        SysFreeString(str);
+
         hr = IDrive_get_IsReady(drive, NULL);
         ok(hr == E_POINTER, "got 0x%08x\n", hr);