diff --git a/src/jsonyx/_manipulator.py b/src/jsonyx/_manipulator.py
index a33b0c9..e72a950 100644
--- a/src/jsonyx/_manipulator.py
+++ b/src/jsonyx/_manipulator.py
@@ -2,6 +2,7 @@
 """JSON manipulator."""
 # TODO(Nice Zombies): add error messages
 # TODO(Nice Zombies): raise JSONSyntaxError
+# TODO(Nice Zombies): remove value comparison
 # TODO(Nice Zombies): update schema ID
 from __future__ import annotations
 
diff --git a/src/jsonyx/_speedups.c b/src/jsonyx/_speedups.c
index af934cb..a9c1b95 100644
--- a/src/jsonyx/_speedups.c
+++ b/src/jsonyx/_speedups.c
@@ -1,5 +1,6 @@
 /* JSON speedups */
 // TODO(Nice Zombies): speed up decoding
+// https://github.com/benfred/py-spy#can-py-spy-profile-native-extensions
 
 #include <Python.h>
 #include <structmember.h>
diff --git a/src/jsonyx/test/test_dumps.py b/src/jsonyx/test/test_dumps.py
index 3128d3d..1cf6e21 100644
--- a/src/jsonyx/test/test_dumps.py
+++ b/src/jsonyx/test/test_dumps.py
@@ -222,8 +222,11 @@ def test_list_indent(
 
 
 @pytest.mark.parametrize(("indent", "expected"), [
+    # Integer
     (0, ""),
     (1, " "),
+
+    # String
     ("\t", "\t"),
 ])
 def test_list_indent_leaves(
@@ -394,8 +397,11 @@ def test_dict_indent(
 
 
 @pytest.mark.parametrize(("indent", "expected"), [
+    # Integer
     (0, ""),
     (1, " "),
+
+    # String
     ("\t", "\t"),
 ])
 def test_dict_indent_leaves(
diff --git a/src/jsonyx/test/test_load_query_value.py b/src/jsonyx/test/test_load_query_value.py
index 15c4209..c5a8571 100644
--- a/src/jsonyx/test/test_load_query_value.py
+++ b/src/jsonyx/test/test_load_query_value.py
@@ -164,7 +164,7 @@ def test_invalid_string(s: str, msg: str, colno: int, end_colno: int) -> None:
     check_syntax_err(exc_info, msg, colno, end_colno)
 
 
-@pytest.mark.parametrize("s", ["", "foo"])
+@pytest.mark.parametrize("s", ["", "NaN"])
 def test_expecting_value(s: str) -> None:
     """Test expecting JSON value."""
     with pytest.raises(JSONSyntaxError) as exc_info:
diff --git a/src/jsonyx/test/test_loads.py b/src/jsonyx/test/test_loads.py
index ce65b3c..9ac87ac 100644
--- a/src/jsonyx/test/test_loads.py
+++ b/src/jsonyx/test/test_loads.py
@@ -281,6 +281,10 @@ def test_array(json: ModuleType, s: str, expected: list[object]) -> None:
 
 
 @pytest.mark.parametrize(("s", "expected"), [
+    # No whitespace
+    ("[]", []),
+    ("[1,2,3]", [1, 2, 3]),
+
     # In empty array
     ("[ ]", []),
 
@@ -360,6 +364,10 @@ def test_object(json: ModuleType, s: str, expected: dict[str, object]) -> None:
 
 
 @pytest.mark.parametrize(("s", "expected"), [
+    # No whitespace
+    ("{}", {}),
+    ('{"a":1,"b":2,"c":3}', {"a": 1, "b": 2, "c": 3}),
+
     # In empty object
     ("{ }", {}),
 
@@ -534,6 +542,9 @@ def test_recursion(json: ModuleType, start: str) -> None:
 
 
 @pytest.mark.parametrize("s", [
+    # No whitespace
+    "0",
+
     # Before value
     " 0",
 
diff --git a/src/jsonyx/test/test_run_filter_query.py b/src/jsonyx/test/test_run_filter_query.py
index 75cc844..c83b9f7 100644
--- a/src/jsonyx/test/test_run_filter_query.py
+++ b/src/jsonyx/test/test_run_filter_query.py
@@ -78,6 +78,9 @@ def test_operator(query: str, keep: bool) -> None:  # noqa: FBT001
 
 
 @pytest.mark.parametrize("query", [
+    # No whitespace
+    "@==0",
+
     # Before operator
     "@ ==0",
 
@@ -86,7 +89,7 @@ def test_operator(query: str, keep: bool) -> None:  # noqa: FBT001
 ])
 def test_operator_whitespace(query: str) -> None:
     """Test whitespace around operator."""
-    assert run_filter_query([], query) == []
+    assert not run_filter_query([], query)
 
 
 @pytest.mark.parametrize(("obj", "keep"), [
@@ -131,11 +134,9 @@ def test_whitespace(query: str) -> None:
     ("$", "Expecting a relative query", 1, -1),
     ("!", "Expecting a relative query", 2, -1),
     ("@?", "Optional marker is not allowed", 2, 3),
-    ("@[@]", "Filter is not allowed", 3, -1),
     ("@ == ", "Expecting value", 6, -1),
     ("@ == $", "Expecting value", 6, -1),
     ("@ == @?", "Optional marker is not allowed", 7, 8),
-    ("@ == @[@]", "Filter is not allowed", 8, -1),
     ("@ && ", "Expecting a relative query", 6, -1),
     ("!@ == @", "Unexpected operator", 4, 6),
     ("@ @ @", "Expecting end of file", 2, -1),