diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index fdc2024..5880715 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -44,7 +44,7 @@ jobs:
         uv venv
         uv pip install . -r dev-requirements.txt
     - name: Run tests
-      run: uv run python -m pytest
+      run: uv run python -m pytest --cov crossandra --cov-report term-missing
     - name: Lint code
       if: always()
       run: |
diff --git a/dev-requirements.txt b/dev-requirements.txt
index 4d6e7cd..0b93279 100644
--- a/dev-requirements.txt
+++ b/dev-requirements.txt
@@ -1,3 +1,4 @@
 mypy ~= 1.10.0
 pytest ~= 8.2.0
+pytest-cov ~= 5.0.0
 ruff ~= 0.4.2
\ No newline at end of file
diff --git a/justfile b/justfile
index a970ffc..073e0b0 100644
--- a/justfile
+++ b/justfile
@@ -7,8 +7,7 @@ install:
     uv pip install . -r dev-requirements.txt
 
 check:
-    python -m pytest
-    mypy --strict crossandra
-    mypy --strict tests
+    python -m pytest --cov crossandra --cov-report term-missing
+    mypy --strict crossandra tests
     ruff check
     ruff format --check
diff --git a/pyproject.toml b/pyproject.toml
index 90258ec..d41cb62 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -18,6 +18,13 @@ archs = ["auto", "aarch64"]
 [tool.cibuildwheel.macos]
 archs = ["x86_64", "universal2"]
 
+[tool.coverage.report]
+exclude_also = [
+    "if TYPE_CHECKING:",
+    "if sys.version_info.*:",
+    "if __name__ == \"__main__\":",
+]
+
 [tool.ruff]
 target-version = "py38"
 
diff --git a/tests/test_api.py b/tests/test_api.py
index 63bdb1f..c8a6611 100644
--- a/tests/test_api.py
+++ b/tests/test_api.py
@@ -14,6 +14,7 @@
     RuleGroup,
     common,
 )
+from crossandra.lib import invert_enum
 from crossandra.rule import IGNORED, NOT_APPLIED
 
 if TYPE_CHECKING:
@@ -198,3 +199,68 @@ def test_rule_group() -> None:
     p, r = RuleGroup((a, b))
 
     assert (a, b) == (x, y) == (p, r)
+
+
+def test_rule_properties() -> None:
+    a = Rule[str]("a")
+    b = Rule[str]("a")
+
+    assert a == b
+    assert a != 1
+    assert isinstance(a | a | b, RuleGroup)
+    assert isinstance(a | (a | b), RuleGroup)
+
+
+@pytest.mark.parametrize(
+    "rule_or_rulegroup",
+    [
+        Rule[str]("a"),
+        RuleGroup((Rule[str]("a"), Rule[str]("b"))),
+    ],
+)
+def test_rule_group_creation_fail(rule_or_rulegroup: Rule[Any] | RuleGroup) -> None:
+    with pytest.raises(TypeError):
+        rule_or_rulegroup | 1
+
+
+def test_invert_enum_with_aliases() -> None:
+    class Test(Enum):
+        FOO = "1"
+        BAR = ("2", "3")
+
+    assert invert_enum(Test) == {"1": Test.FOO, "2": Test.BAR, "3": Test.BAR}
+
+
+def test_tokenize_lines() -> None:
+    assert Crossandra(rules=[common.WORD], ignore_whitespace=True).tokenize_lines(
+        "a b\nc\rde"
+    ) == [["a", "b"], ["c"], ["de"]]
+
+
+def test_break_path() -> None:
+    class Test(Enum):
+        X = "ABC"
+        Y = "A"
+        Z = "B"
+
+    assert Crossandra(Test).tokenize("ABABAABABC") == [
+        Test.Y,
+        Test.Z,
+        Test.Y,
+        Test.Z,
+        Test.Y,
+        Test.Y,
+        Test.Z,
+        Test.X,
+    ]
+
+
+def test_tokenize_fast_with_ignored() -> None:
+    class Test(Enum):
+        FOO = "x"
+        BAR = "y"
+
+    assert Crossandra(Test, ignored_characters="z").tokenize("xzy") == [
+        Test.FOO,
+        Test.BAR,
+    ]