update test SCDsignal with new restriction

code/classes/SCDsignal/SCDsignal_test.m

 classdef SCDsignal_test < matlab.unittest.TestCase
   
   properties (MethodSetupParameter)
-    type = {'single','double','logical','double'};
+    type = {'int8','single','int32','single'};
     m    = {1,       100,      3,        3      };
     n    = {1,         1,      3,       10      };
   end
@@ -134,10 +134,10 @@ classdef SCDsignal_test < matlab.unittest.TestCase
     end
     
     function test_struct_to_bus(testCase)
-      % Test creation of complex bus from structure which may contain
+      %% Test creation of complex bus from structure which may contain
       % SCDsignals at leaves
-      S_sub = struct('sig1',{testCase.sig},'sig2',rand(5,5));
-      S = struct('a',1,'b',ones(3,1),'c',true(4,2),'sub',S_sub,'sig',{SCDsignal(ones(4,1))});
+      S_sub = struct('sig1',{testCase.sig},'sig2',single(rand(5,5)));
+      S = struct('a',single(1),'b',single(ones(3,1)),'c',true(4,2),'sub',S_sub,'sig',{SCDsignal(single(ones(4,1)))});
       testCase.verifyWarningFree(@() SCDsignal_struct_to_bus(S,'myTestBus','Bus with several data types for testing'));
     end
   end