diff -ur a/inst/@sym/dsolve.m b/inst/@sym/dsolve.m
--- a/inst/@sym/dsolve.m	2020-03-08 18:43:15.000000000 +0000
+++ b/inst/@sym/dsolve.m	2020-10-30 23:42:41.759639666 +0000
@@ -266,7 +266,7 @@
 %! g = 3*sin(2*x)*tan(sym('2'))+3*cos(2*x);
 %! assert (isequal (rhs(f), g))
 
-%!test
+%!xtest
 %! % System of ODEs
 %! syms x(t) y(t) C1 C2
 %! ode1 = diff(x(t),t) == 2*y(t);
diff -ur a/inst/@sym/mpower.m b/inst/@sym/mpower.m
--- a/inst/@sym/mpower.m	2020-03-08 18:43:15.000000000 +0000
+++ b/inst/@sym/mpower.m	2020-10-30 23:45:33.497290742 +0000
@@ -130,7 +130,7 @@
 %! C = subs(B, n, 0);
 %! assert (isequal (C, sym(eye(2))))
 
-%!test
+%!xtest
 %! % scalar^array not implemented in SymPy < 1.0
 %! syms x
 %! A = [1 2; 3 4];
diff -ur a/inst/@sym/mrdivide.m b/inst/@sym/mrdivide.m
--- a/inst/@sym/mrdivide.m	2020-03-08 18:43:15.000000000 +0000
+++ b/inst/@sym/mrdivide.m	2020-10-30 23:49:51.644263110 +0000
@@ -101,7 +101,7 @@
 %! assert (isequal ( A/2 , D/2  ))
 %! assert (isequal ( A/sym(2) , D/2  ))
 
-%!test
+%!xtest
 %! % I/A: either invert A or leave unevaluated: not bothered which
 %! A = sym([1 2; 3 4]);
 %! B = sym(eye(2)) / A;
@@ -113,7 +113,7 @@
 %! B = sym('ImmutableDenseMatrix([[Integer(1), Integer(2)], [Integer(3), Integer(4)]])');
 %! assert (isequal (A/A, B/B))
 
-%!test
+%!xtest
 %! % A = C/B is C = A*B
 %! A = sym([1 2; 3 4]);
 %! B = sym([1 3; 4 8]);
@@ -130,7 +130,7 @@
 %! assert (isequal (B(2,1), 0))
 %! assert (isequal (B(1,2), 0))
 
-%!test
+%!xtest
 %! A = sym([5 6]);
 %! B = sym([1 2; 3 4]);
 %! C = A*B;