1 files changed, 69 insertions, 0 deletions
diff --git a/tests/builder/cache.test.py b/tests/builder/cache.test.py
new file mode 100644
index 0000000..80862d3
--- /dev/null
+++ b/tests/builder/cache.test.py
@@ -0,0 +1,69 @@
+"""Tests for the lazy :class:`Regex` cache on :class:`BuilderCore`."""
+
+from edify import Pattern, RegexBuilder
+
+
+def test_repeated_lazy_regex_calls_return_the_same_instance():
+    builder = RegexBuilder().digit()
+    first = builder._lazy_regex()
+    second = builder._lazy_regex()
+    third = builder._lazy_regex()
+    assert first is second
+    assert second is third
+
+
+def test_repeated_matcher_calls_reuse_the_cached_regex():
+    builder = RegexBuilder().digit()
+    builder.match("1")
+    cached = builder._cached_regex
+    builder.search("2")
+    builder.findall("3")
+    builder.test("4")
+    assert builder._cached_regex is cached
+
+
+def test_pattern_lazy_regex_is_memoised_too():
+    pattern = Pattern().word()
+    first = pattern._lazy_regex()
+    second = pattern._lazy_regex()
+    assert first is second
+
+
+def test_a_forked_builder_gets_a_fresh_cache_slot():
+    original = RegexBuilder().digit()
+    original.match("1")
+    assert original._cached_regex is not None
+    forked = original.fork()
+    assert forked._cached_regex is None
+
+
+def test_a_copied_builder_gets_a_fresh_cache_slot():
+    original = RegexBuilder().digit()
+    original.match("1")
+    copied = original.copy()
+    assert copied._cached_regex is None
+
+
+def test_a_chain_extension_gets_a_fresh_cache_slot():
+    original = RegexBuilder().digit()
+    original.match("1")
+    extended = original.word()
+    assert extended._cached_regex is None
+
+
+def test_a_fresh_builder_starts_without_a_cached_regex():
+    builder = RegexBuilder()
+    assert builder._cached_regex is None
+
+
+def test_calling_to_regex_directly_does_not_populate_the_cache():
+    builder = RegexBuilder().digit()
+    _ = builder.to_regex()
+    assert builder._cached_regex is None
+
+
+def test_lazy_regex_produces_a_regex_that_matches_the_pattern():
+    builder = RegexBuilder().digit()
+    result = builder._lazy_regex()
+    assert result.source == "\\d"
+    assert result.match("7") is not None