           else
             3
 
-        # FIXME - the test case below once passed but now fails.
-        # The test is disabled by using xit rather than it.
-        # Change xit to it, fix the problem and remove this comment.
-        xit 'should calculate the summary grade', ->
+        it 'should calculate the summary grade', ->
           for df in [1..3]
             for mc in [1..3]
               for nc in [1..2]

        # @returns the expected summary grade
        expectedSummaryGrade = (grade) ->
          cumulativeGrade = grade.differentiation + grade.mitoticCount +
            grade.necrosis_score
          if cumulativeGrade < 4
            1
          else if cumulativeGrade < 6

                  grade:
                    differentiation: df
                    mitoticCount: mc
                    necrosisScore: nc
                expected = expectedSummaryGrade(tnm.grade)
                actual = TNM.summaryGrade(tnm)
                expect(actual, "The summary grade for" +
