1 files changed, 47 insertions, 0 deletions
diff --git a/tests/yaml_rewrite_test.py b/tests/yaml_rewrite_test.py
new file mode 100644
index 0000000..d0f6841
--- /dev/null
+++ b/tests/yaml_rewrite_test.py
@@ -0,0 +1,47 @@
+from __future__ import annotations
+
+import pytest
+
+from pre_commit.yaml import yaml_compose
+from pre_commit.yaml_rewrite import MappingKey
+from pre_commit.yaml_rewrite import MappingValue
+from pre_commit.yaml_rewrite import match
+from pre_commit.yaml_rewrite import SequenceItem
+
+
+def test_match_produces_scalar_values_only():
+    src = '''\
+-   name: foo
+-   name: [not, foo]  # not a scalar: should be skipped!
+-   name: bar
+'''
+    matcher = (SequenceItem(), MappingValue('name'))
+    ret = [n.value for n in match(yaml_compose(src), matcher)]
+    assert ret == ['foo', 'bar']
+
+
+@pytest.mark.parametrize('cls', (MappingKey, MappingValue))
+def test_mapping_not_a_map(cls):
+    m = cls('s')
+    assert list(m.match(yaml_compose('[foo]'))) == []
+
+
+def test_sequence_item_not_a_sequence():
+    assert list(SequenceItem().match(yaml_compose('s: val'))) == []
+
+
+def test_mapping_key():
+    m = MappingKey('s')
+    ret = [n.value for n in m.match(yaml_compose('s: val\nt: val2'))]
+    assert ret == ['s']
+
+
+def test_mapping_value():
+    m = MappingValue('s')
+    ret = [n.value for n in m.match(yaml_compose('s: val\nt: val2'))]
+    assert ret == ['val']
+
+
+def test_sequence_item():
+    ret = [n.value for n in SequenceItem().match(yaml_compose('[a, b, c]'))]
+    assert ret == ['a', 'b', 'c']