Search service's DateConstraint#toString depends on the JVM format locale to work correctly

The DateConstraint object uses DateFormat.getDateInstance() to construct the query clause by which to search, resulting in e.g. "(date publicationDate >= Sep 28, 2012, resolution = DAY)"

So it takes the default formatting locale from the local JVM which makes it depend on that locale being English.

This was encountered on my machine that had failing tests, caused by my JVM's formatting locale being Dutch: org.onehippo.cms7.services.search.query.QueryTest#testStringVisitor resulted in

org.junit.ComparisonFailure: 
Expected : of type hippo:document select author where (text title contains ard) and (text [any] contains haha) and ((int count <= 5) or (date publicationDate >= Sep 28, 2012, resolution = DAY))
Actual   : of type hippo:document select author where (text title contains ard) and (text [any] contains haha) and ((int count <= 5) or (date publicationDate >= 28-sep-2012, resolution = DAY))

Note "Sep 28, 2012" versus "28-sep-2012"

Note it turns out that this code, which is in the toString method, is not executed functionally (i.e. in advanced search) so does not break anything.