     y.equals(x).should.be.true
 
   it 'should properly calculate begins/begun by except', ->
-    (@dateTimeBeginsExcept.exec(@ctx) == null).should.be.true
+    should(@dateTimeBeginsExcept.exec(@ctx)).be.null
 
   it 'should properly calculate includes/included by except', ->
-    (@dateTimeDuringExcept.exec(@ctx) == null).should.be.true
+    should(@dateTimeDuringExcept.exec(@ctx)).be.null
 
   it 'should properly calculate ends/ended by except', ->
-    (@dateTimeEndsExcept.exec(@ctx) == null).should.be.true
+    should(@dateTimeEndsExcept.exec(@ctx)).be.null
 
 # TODO
 # it 'should properly handle imprecision', ->

  @beforeEach ->
    setup @, data

   it 'should properly calculate sameAs except', ->
    (@dateTimeSameAsExcept.exec(@ctx) == null).should.be.true

  it 'should properly calculate before/after except', ->
    @dateTimeBeforeExcept.exec(@ctx).should.eql new Interval(new DateTime(2012, 1, 1, 0, 0, 0, 0), new DateTime(2012, 4, 1, 0, 0, 0, 0))

    y.equals(x).should.be.true

  it 'should properly calculate before/after unions', ->
    should(@intBeforeUnion.exec(@ctx)).be.null

  it 'should properly calculate meets unions', ->
    x = @intFullInterval.exec(@ctx)
