@Before
    public void setUp() {
        c=new FieldMatchMetricsComputer();
        StringBuilder field = new StringBuilder();
        for (int i = 0; i < 150; i++)
            field.append("t" + i + " ");
        c.compute("query", field.toString()); // Just to set the field value
    }
The "semantic distance" refers to the non-continuous distance from a token
to the next token used by the string match metrics algorithm. This class
tests invariants which must hold for any such distance metric as well as specifics
for the currently used distance metric.

@author bratseth
searchlib/src/test/java/com/yahoo/searchlib/ranking/features/fieldmatch/SemanticDistanceTestCase.java