add tests for drop-genotypes option

tests/test_bcftools_validation.py

@@ -49,6 +49,10 @@ def run_vcztools(args: str) -> str:
                 "view --no-version -e '(FMT/DP >= 8 | FMT/GQ>40) && POS > 100000'",
                 "sample.vcf.gz"
         ),
+        (
+                "view --no-version -G",
+                "sample.vcf.gz"
+        ),
     ]
 )
 # fmt: on

tests/test_vcf_writer.py

@@ -174,6 +174,18 @@ def test_write_vcf__samples(tmp_path, samples, expected_genotypes):
     assert variant.genotypes == expected_genotypes
 
 
+def test_write_vcf__no_samples(tmp_path):
+    original = pathlib.Path("tests/data/vcf") / "sample.vcf.gz"
+    vcz = vcz_path_cache(original)
+    output = tmp_path.joinpath("output.vcf")
+
+    write_vcf(vcz, output, drop_genotypes=True)
+
+    v = VCF(output)
+
+    assert v.samples == []
+
+
 @pytest.mark.parametrize(
     ("regions", "targets", "samples", "include", "expected_chrom_pos"),
     [