1 files changed, 63 insertions, 0 deletions
diff --git a/tests/builder/cache.test.py b/tests/builder/cache.test.py
new file mode 100644
index 0000000..700a8e4
--- /dev/null
+++ b/tests/builder/cache.test.py
@@ -0,0 +1,63 @@
+"""Tests for the per-instance lazy compile cache."""
+
+from edify import Pattern, RegexBuilder
+
+
+def test_two_no_kwargs_to_regex_calls_return_the_same_instance():
+    builder = RegexBuilder().one_or_more().digit()
+    first = builder.to_regex()
+    second = builder.to_regex()
+    assert first is second
+
+
+def test_matcher_call_shares_the_cache_with_to_regex():
+    builder = RegexBuilder().one_or_more().digit()
+    first = builder.to_regex()
+    builder.test("42")
+    assert builder.to_regex() is first
+
+
+def test_kwarg_call_bypasses_the_cache_and_never_populates_it():
+    builder = RegexBuilder().string("ABC")
+    with_kwargs = builder.to_regex(ignore_case=True)
+    default = builder.to_regex()
+    assert with_kwargs is not default
+    assert builder.to_regex() is default
+
+
+def test_regex_engine_kwarg_bypasses_the_cache():
+    builder = RegexBuilder().digit()
+    default = builder.to_regex()
+    via_regex = builder.to_regex(engine="regex")
+    assert default is not via_regex
+    assert default.engine == "re"
+    assert via_regex.engine == "regex"
+
+
+def test_kwarg_call_first_still_leaves_a_default_no_kwargs_call_cacheable():
+    builder = RegexBuilder().string("hi")
+    builder.to_regex(ignore_case=True)
+    first_default = builder.to_regex()
+    second_default = builder.to_regex()
+    assert first_default is second_default
+
+
+def test_forked_builder_gets_its_own_empty_cache():
+    parent = RegexBuilder().digit()
+    parent.to_regex()
+    child = parent.fork()
+    assert child.to_regex() is child.to_regex()
+    assert parent.to_regex() is not child.to_regex()
+
+
+def test_chain_step_yields_a_fresh_cache_slot():
+    root = RegexBuilder().digit()
+    original = root.to_regex()
+    extended = root.word()
+    extended_regex = extended.to_regex()
+    assert extended_regex is not original
+
+
+def test_pattern_also_caches_across_repeat_to_regex_calls():
+    pattern = Pattern().string("hi")
+    assert pattern.to_regex() is pattern.to_regex()