test(qb): Add tests for qb section (#74)

test(qb): Add missing tests for qb directory

* Add a GROUP BY test without Columns
* Add LtFunc test
* Add LtOrEqFunc test
* Add GtFunc test
* Add GtOrEqFunc test
* Add a Select with a AS between one column test
* Add a Order By DESC test
* Add Sum test
* Add Avg test
* Add Max test
* Add 2 tests for FuncColumn
* Add SetNamed test
* Add AddFunc test
* Add RemoveFunc test
* Add TTL and TimestampNamed test
* Add TTLNamed and Timestamp test
* Add TTL with negative or no duration test
* Add LtFunc test
* Add LtOrEqFunc test
* Add GtFunc test
* Add GtOrEqFunc test
* Add a Select with a AS between one column test
* Add a Order By DESC test
* Add Sum test
* Add Avg test
* Add Max test
* Add SetNamed test
* Add AddFunc test
* Add RemoveFunc test
* Add TTL and TimestampNamed test
* Add TTLNamed and Timestamp test
* Add TTL with negative or no duration test
* Add LtFunc test
* Add LtOrEqFunc test
* Add GtFunc test
* Add GtOrEqFunc test
* Add a Select with a AS between one column test
* Add a Order By DESC test
* Add Sum test
* Add Avg test
* Add Max test
* Add 2 tests for FuncColumn
* Add SetNamed test
* Add AddFunc test
* Add RemoveFunc test
* In qb/select.go, if there are no colums and the query have a GroupBy
statement then the query will be malformated.
* In qb/utils.go, refactor writeCql with a strings.Join call.

Fixes #78

qb/cmp_test.go

@@ -151,6 +151,24 @@ func TestCmp(t *testing.T) {
 			C: EqFunc("eq", Now()),
 			S: "eq=now()",
 		},
+		{
+			C: LtFunc("eq", Now()),
+			S: "eq<now()",
+		},
+		{
+			C: LtOrEqFunc("eq", MaxTimeuuid("arg0")),
+			S: "eq<=maxTimeuuid(?)",
+			N: []string{"arg0"},
+		},
+		{
+			C: GtFunc("eq", Now()),
+			S: "eq>now()",
+		},
+		{
+			C: GtOrEqFunc("eq", MaxTimeuuid("arg0")),
+			S: "eq>=maxTimeuuid(?)",
+			N: []string{"arg0"},
+		},
 	}
 
 	buf := bytes.Buffer{}