Adding field_type combos example + test skeleton

Author: jeromekelleher

tests/data/vcf/field_type_combos.vcf.gz

@@ -654,6 +654,12 @@ def ds(self, tmp_path_factory):
         vcf.convert_vcf([self.data_path], out)
         return sg.load_dataset(out)
 
+    def test_info_string1(self, ds):
+        print(repr(ds["variant_IS1"].values))
+
+    def test_info_string2(self, ds):
+        print(repr(ds["variant_IS2"].values))
+
 
 @pytest.mark.parametrize(
     "name",