Update implicit test

This adds a test that only passes now. We also need to change the
seventh test because there is now a different preferred representation
when combining a trace.

Signed-off-by: Connor Behan <[email protected]>

Author: cbehan

tests/implicit.cdb

@@ -66,7 +66,7 @@ def test06():
     {a,b}::Indices(vector);
     ex:=(A)_{a b} (B)_{b a};
     combine(_);
-    tst:= (A B)_{b b} - @(ex);
+    tst:= (B A)_{b b} - @(ex);
     assert(tst==0)
     print("Test 06 passed")
 
@@ -86,3 +86,14 @@ def test07():
 
 test07()
 
+def test08():
+    __cdbkernel__=create_scope()
+    {a,b}::Indices(vector);
+    ex:=(u)_{a} (M)^{a b} (v)_{b};
+    combine(_);
+    tst:= (u M v) - @(ex);
+    assert(tst==0)
+    print("Test 08 passed")
+
+test08()
+