source: class GraphPatternTest  {
  
      @Test
      public void testTuplePatternsAreOrdered() {
  
target:         GraphPattern<String, String> pattern = new GraphPattern<>(
                  tuplePattern("?x", "knows", "?y"),
                  tuplePattern("?x", "age", "21")
          );
          assertEquals(2, pattern.getPatterns().length);
          assertEquals(3, pattern.getPatterns()[0].getPattern().length);
          assertEquals(3, pattern.getPatterns()[1].getPattern().length);
          assertEquals("?x", pattern.getPatterns()[0].getPattern()[0].getVariable());
          assertNull(pattern.getPatterns()[0].getPattern()[0].getConstant());
          assertNull(pattern.getPatterns()[0].getPattern()[1].getVariable());
          assertEquals("knows", pattern.getPatterns()[0].getPattern()[1].getConstant());
          assertEquals("?y", pattern.getPatterns()[0].getPattern()[2].getVariable());
          assertNull(pattern.getPatterns()[0].getPattern()[2].getConstant());
          assertEquals("?x", pattern.getPatterns()[1].getPattern()[0].getVariable());
          assertNull(pattern.getPatterns()[1].getPattern()[0].getConstant());
          assertNull(pattern.getPatterns()[1].getPattern()[1].getVariable());
          assertEquals("age", pattern.getPatterns()[1].getPattern()[1].getConstant());
          assertNull(pattern.getPatterns()[1].getPattern()[2].getVariable());
          assertEquals("21", pattern.getPatterns()[1].getPattern()[2].getConstant());
      }
  
  }