1 files changed, 50 insertions, 0 deletions
diff --git a/tests/builder/equality.test.py b/tests/builder/equality.test.py
new file mode 100644
index 0000000..717d1ae
--- /dev/null
+++ b/tests/builder/equality.test.py
@@ -0,0 +1,50 @@
+"""Tests for value-based ``__eq__`` and ``__hash__`` on :class:`BuilderCore`."""
+
+from edify import Pattern, RegexBuilder
+
+
+def test_two_builders_with_the_same_chain_are_equal():
+    assert RegexBuilder().digit() == RegexBuilder().digit()
+
+
+def test_two_patterns_with_the_same_chain_are_equal():
+    assert Pattern().digit() == Pattern().digit()
+
+
+def test_builders_with_different_chains_are_not_equal():
+    assert RegexBuilder().digit() != RegexBuilder().word()
+
+
+def test_equal_builders_produce_equal_hashes():
+    assert hash(RegexBuilder().digit()) == hash(RegexBuilder().digit())
+
+
+def test_a_builder_is_usable_as_a_dict_key():
+    lookup = {RegexBuilder().digit(): "digit-key"}
+    assert lookup[RegexBuilder().digit()] == "digit-key"
+
+
+def test_a_builder_can_be_deduplicated_in_a_set():
+    dedup = {RegexBuilder().digit(), RegexBuilder().digit(), RegexBuilder().word()}
+    assert len(dedup) == 2
+
+
+def test_a_pattern_and_a_regex_builder_with_the_same_state_compare_equal():
+    assert Pattern().digit() == RegexBuilder().digit()
+
+
+def test_a_builder_compared_to_a_non_builder_is_not_equal():
+    assert (RegexBuilder().digit() == "foo") is False
+    assert (RegexBuilder().digit() == 42) is False
+
+
+def test_a_builder_compared_to_a_non_builder_returns_not_implemented_from_the_dunder():
+    result = RegexBuilder().digit().__eq__("foo")
+    assert result is NotImplemented
+
+
+def test_hash_of_two_flags_that_differ_are_distinct():
+    a = RegexBuilder().ignore_case().digit()
+    b = RegexBuilder().digit()
+    assert a != b
+    assert hash(a) != hash(b)