Add test_variant_str_no_samples and test_variant_str_no_site

python/tests/test_genotypes.py

@@ -2153,6 +2153,33 @@ def test_variant_str(self):
             str(v),
         )
 
+    def test_variant_str_no_samples(self):
+        tables = tskit.TableCollection(10)
+        tables.nodes.add_row(flags=tskit.NODE_IS_SAMPLE, time=0)
+        tables.sites.add_row(position=5, ancestral_state="A")
+        ts = tables.tree_sequence()
+        v = next(ts.variants(samples=[]))
+        for allele in v.alleles:
+            if allele is not None:
+                assert (
+                    re.search(
+                        rf"║Samples with allele '{allele}'\s*│\s*0\s*\(nan\%\)║", str(v)
+                    )
+                    is not None
+                )
+
+    def test_variant_str_no_site():
+        tables = tskit.TableCollection(10)
+        ts = tables.tree_sequence()
+        v = tskit.Variant(ts)
+        s = str(v)
+        assert len(s.splitlines()) == 3
+        assert (
+            "This variant has not yet been decoded at a specific site,"
+            + "call Variant.decode to set the site"
+            in s
+        )
+
     def test_variant_html_repr(self, ts_fixture):
         v = next(ts_fixture.variants())
         html = v._repr_html_()