diff --git a/SYMBOLS_MANIFEST.txt b/SYMBOLS_MANIFEST.txt
index 54cafb2e5..1369d207f 100644
--- a/SYMBOLS_MANIFEST.txt
+++ b/SYMBOLS_MANIFEST.txt
@@ -187,6 +187,7 @@ System`Brown
 System`ButtonBox
 System`Byte
 System`ByteArray
+System`ByteArrayQ
 System`ByteCount
 System`ByteOrdering
 System`C
diff --git a/mathics/builtin/arithmetic.py b/mathics/builtin/arithmetic.py
index d5ea760ba..1d4e9c52c 100644
--- a/mathics/builtin/arithmetic.py
+++ b/mathics/builtin/arithmetic.py
@@ -73,6 +73,7 @@
     SymbolTable,
     SymbolUndefined,
 )
+from mathics.eval.arithmetic import eval_RealValuedNumberQ
 from mathics.eval.inference import get_assumptions_list
 from mathics.eval.nevaluator import eval_N
 from mathics.eval.numeric import eval_Sign
@@ -961,11 +962,7 @@ class RealValuedNumberQ(Test):
     summary_text = "test whether an expression is a real number"
 
     def test(self, expr) -> bool:
-        return (
-            isinstance(expr, (Integer, Rational, Real))
-            or expr.has_form("Underflow", 0)
-            or expr.has_form("Overflow", 0)
-        )
+        return eval_RealValuedNumberQ(expr)
 
 
 class Sum(IterationFunction, SympyFunction, PrefixOperator):
diff --git a/mathics/builtin/atomic/atomic.py b/mathics/builtin/atomic/atomic.py
index 71e4df3f5..d36fbb294 100644
--- a/mathics/builtin/atomic/atomic.py
+++ b/mathics/builtin/atomic/atomic.py
@@ -4,7 +4,7 @@
 """
 
 from mathics.core.builtin import Builtin, Test
-from mathics.core.symbols import Atom
+from mathics.eval.atomic.atomic import eval_AtomQ
 
 
 class AtomQ(Test):
@@ -57,7 +57,7 @@ class AtomQ(Test):
     summary_text = "test whether an expression is an atom"
 
     def test(self, expr) -> bool:
-        return isinstance(expr, Atom)
+        return eval_AtomQ(expr)
 
 
 class Head(Builtin):
diff --git a/mathics/builtin/atomic/symbols.py b/mathics/builtin/atomic/symbols.py
index 04b77a67b..628bc0af0 100644
--- a/mathics/builtin/atomic/symbols.py
+++ b/mathics/builtin/atomic/symbols.py
@@ -6,7 +6,7 @@
 or namespace, and can have a variety of type of values and attributes.
 """
 import re
-from typing import Callable, List, Optional
+from typing import Callable, Optional
 
 from mathics_scanner.tokeniser import NAMES_WILDCARDS, is_symbol_name
 
@@ -45,20 +45,21 @@
     SymbolGrid,
     SymbolInputForm,
     SymbolLeft,
+    SymbolMissing,
     SymbolOptions,
     SymbolRule,
     SymbolSet,
 )
 from mathics.doc.online import online_doc_string
+from mathics.eval.atomic.symbols import eval_SymbolQ
 from mathics.eval.stackframe import get_eval_Expression
 
-SymbolMissing = Symbol("System`Missing")
 SymbolUnknownSymbol = Symbol("System`UnknownSymbol")
 
 
 def gather_and_format_definition_rules(
     symbol: Symbol, evaluation: Evaluation
-) -> Optional[List[Expression]]:
+) -> Optional[list[Expression]]:
     """Return a list of lines describing the definition of `symbol`"""
     lines = []
 
@@ -727,7 +728,7 @@ class SymbolQ(Test):
     summary_text = "test whether is a symbol"
 
     def test(self, expr) -> bool:
-        return isinstance(expr, Symbol)
+        return eval_SymbolQ(expr)
 
 
 class ValueQ(Builtin):
diff --git a/mathics/builtin/binary/__init__.py b/mathics/builtin/binary/__init__.py
index 8916f0d5a..3bd4705cc 100644
--- a/mathics/builtin/binary/__init__.py
+++ b/mathics/builtin/binary/__init__.py
@@ -1,5 +1,4 @@
 # -*- coding: utf-8 -*-
-
 """
 Binary Data
 
diff --git a/mathics/builtin/binary/bytearray.py b/mathics/builtin/binary/bytearray.py
index ae3a4e947..8e7af122f 100644
--- a/mathics/builtin/binary/bytearray.py
+++ b/mathics/builtin/binary/bytearray.py
@@ -6,10 +6,12 @@
 from typing import Optional
 
 from mathics.core.atoms import ByteArray, Integer, String
-from mathics.core.builtin import Builtin
+from mathics.core.attributes import A_PROTECTED
+from mathics.core.builtin import Builtin, Test
 from mathics.core.convert.expression import to_mathics_list
 from mathics.core.evaluation import Evaluation
 from mathics.core.list import ListExpression
+from mathics.eval.binary.bytearray import eval_ByteArrayQ
 
 
 class ByteArray_(Builtin):
@@ -54,6 +56,8 @@ class ByteArray_(Builtin):
         ),
     }
 
+    expected_args = 1
+    eval_error = Builtin.generic_argument_error
     name = "ByteArray"
     summary_text = "array of bytes"
 
@@ -88,4 +92,33 @@ def eval_list(self, values, evaluation) -> Optional[ByteArray]:
         return ba
 
 
-# TODO: BaseEncode, BaseDecode, ByteArrayQ, ByteArrayToString, StringToByteArray, ImportByteArray, ExportByteArray
+class ByteArrayQ(Test):
+    r"""
+    <url>:WMA link:
+    https://reference.wolfram.com/language/ref/ByteArrayQ.html</url>
+
+    <dl>
+      <dt>'ByteArrayQ'[{$expr$}]
+      <dd> returns True if $expr$ is a ByteArray object, and False otherwise.
+    </dl>
+
+    >> ByteArrayQ[ByteArray[Range[16]]]
+     = True
+
+    >> ByteArrayQ[Range[3]]
+     = False
+
+    >> ByteArrayQ[ByteArray["xyz"]]
+     : The argument at position 1 in ByteArray[xyz] should be a vector of unsigned byte values or a Base64-encoded string.
+     = False
+    """
+
+    attributes = A_PROTECTED
+    summary_text = "test whether an expression is a ByteArray"
+
+    def test(self, expr) -> bool:
+        """Return True if expr is a ByteArray atom."""
+        return eval_ByteArrayQ(expr)
+
+
+# TODO: BaseEncode, BaseDecode, ByteArrayToString, StringToByteArray, ImportByteArray, ExportByteArray
diff --git a/mathics/core/builtin.py b/mathics/core/builtin.py
index 0c30758a3..125cc9e5e 100644
--- a/mathics/core/builtin.py
+++ b/mathics/core/builtin.py
@@ -14,18 +14,7 @@
 from functools import total_ordering
 from itertools import chain
 from types import ModuleType
-from typing import (
-    Any,
-    Callable,
-    Dict,
-    Iterable,
-    List,
-    Optional,
-    Sequence,
-    Tuple,
-    Union,
-    cast,
-)
+from typing import Any, Callable, Iterable, List, Optional, Sequence, Tuple, Union, cast
 
 import mpmath
 import sympy
@@ -205,16 +194,16 @@ def eval_with_options(x, evaluation: Evaluation, options: dict):
     _is_numeric: bool = False
     attributes: int = A_PROTECTED
     context: str = ""
-    defaults: Dict[Optional[int], str] = {}
+    defaults: dict[Optional[int], str] = {}
 
     # Number of arguments expected. -1 is used for an arbitrary number.
     expected_args: Union[int, Tuple[int, int], range] = -1
 
-    formats: Dict[str, Any] = {}
-    messages: Dict[str, Any] = {}
+    formats: dict[str, Any] = {}
+    messages: dict[str, Any] = {}
     name: Optional[str] = None
-    options: Dict[str, Any] = {}
-    rules: Dict[str, Any] = {}
+    options: dict[str, Any] = {}
+    rules: dict[str, Any] = {}
 
     def __getnewargs_ex__(self):
         return tuple(), {
@@ -363,7 +352,7 @@ def contextify_form_name(f):
                 forms = [""]
             return forms, pattern
 
-        formatvalues: Dict[str, List[BaseRule]] = {"": []}
+        formatvalues: dict[str, List[BaseRule]] = {"": []}
         for pattern, function in self.get_functions("format_"):
             forms, pattern = extract_forms(pattern)
             pat_attr = attributes if pattern.get_head_name() == name else None
@@ -676,7 +665,7 @@ def is_literal(self) -> bool:
 
 
 class BuiltinElement(Builtin, BaseElement):
-    options: Dict[str, Any]
+    options: dict[str, Any]
 
     def __new__(cls, *args, **kwargs):
         new_kwargs = kwargs.copy()
@@ -707,7 +696,7 @@ def __hash__(self):
 class SympyObject(Builtin):
     sympy_name: Optional[str] = None
 
-    mathics_to_sympy: Dict[str, str] = {}
+    mathics_to_sympy: dict[str, str] = {}
 
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
@@ -715,7 +704,7 @@ def __init__(self, *args, **kwargs):
             self.sympy_name = strip_context(self.get_name()).lower()
         self.mathics_to_sympy[self.__class__.__name__] = self.sympy_name
 
-    def get_sympy_names(self) -> List[str]:
+    def get_sympy_names(self) -> list[str]:
         if self.sympy_name:
             return [self.sympy_name]
         return []
@@ -848,8 +837,8 @@ def eval(self, z, evaluation: Evaluation):
 
 
 class MPMathMultiFunction(MPMathFunction):
-    sympy_names: Optional[Dict[int, str]] = None
-    mpmath_names: Optional[Dict[int, str]] = None
+    sympy_names: Optional[dict[int, str]] = None
+    mpmath_names: Optional[dict[int, str]] = None
 
     def get_sympy_names(self):
         if self.sympy_names is None:
@@ -972,7 +961,7 @@ def has_option(options, name, evaluation):
     return get_option(options, name, evaluation, evaluate=False) is not None
 
 
-mathics_to_python: Dict[str, Any] = {}  # here we have: name -> string
+mathics_to_python: dict[str, Any] = {}  # here we have: name -> string
 
 
 @total_ordering
@@ -1638,8 +1627,8 @@ def add_no_meaning_builtin_classes(
 class PatternObject(BuiltinElement, BasePattern):
     needs_verbatim = True
 
-    arg_counts: List[int] = []
-    options: Dict[str, Any]
+    arg_counts: list[int] = []
+    options: dict[str, Any]
 
     def init(self, expr: Expression, evaluation: Optional[Evaluation] = None):
         super().init(expr, evaluation=evaluation)
@@ -1705,6 +1694,9 @@ def pattern_precedence(self) -> tuple:
 
 
 class Test(Builtin, ABC):
+    expected_args = 1
+    eval_error = Builtin.generic_argument_error
+
     def eval(self, expr, evaluation: Evaluation) -> Optional[BooleanType]:
         # Note: in the docstring below, we need to use %(name)s for
         # subclasses like ExactNumberQ to work with function-application
diff --git a/mathics/eval/arithmetic.py b/mathics/eval/arithmetic.py
index 8e09d28ea..d552b2f52 100644
--- a/mathics/eval/arithmetic.py
+++ b/mathics/eval/arithmetic.py
@@ -184,6 +184,14 @@ def eval_negate_number(n: Number) -> Number:
     return eval_multiply_numbers(IntegerM1, n)
 
 
+def eval_RealValuedNumberQ(expr) -> bool:
+    return (
+        isinstance(expr, (Integer, Rational, Real))
+        or expr.has_form("Underflow", 0)
+        or expr.has_form("Overflow", 0)
+    )
+
+
 def segregate_numbers(
     *elements: BaseElement,
 ) -> Tuple[List[Number], List[BaseElement]]:
diff --git a/mathics/eval/atomic/atomic.py b/mathics/eval/atomic/atomic.py
new file mode 100644
index 000000000..a8b541016
--- /dev/null
+++ b/mathics/eval/atomic/atomic.py
@@ -0,0 +1,10 @@
+"""
+Evaluation methods for mathics.builtin.atomic.atomic.
+"""
+
+from mathics.core.symbols import Atom
+
+
+def eval_AtomQ(expr) -> bool:
+    """Return True if expr is an Atom."""
+    return isinstance(expr, Atom)
diff --git a/mathics/eval/atomic/symbols.py b/mathics/eval/atomic/symbols.py
new file mode 100644
index 000000000..9d94a58aa
--- /dev/null
+++ b/mathics/eval/atomic/symbols.py
@@ -0,0 +1,10 @@
+"""
+Evaluation methods for mathics.builtin.atomic.atomic.
+"""
+
+from mathics.core.symbols import Symbol
+
+
+def eval_SymbolQ(expr) -> bool:
+    """Return True if expr is an Symbol."""
+    return isinstance(expr, Symbol)
diff --git a/mathics/eval/binary/bytearray.py b/mathics/eval/binary/bytearray.py
new file mode 100644
index 000000000..e28c6f926
--- /dev/null
+++ b/mathics/eval/binary/bytearray.py
@@ -0,0 +1,10 @@
+"""
+Evaluation methods for mathics.builtin.binary.bytearray.
+"""
+
+from mathics.core.atoms import ByteArray
+
+
+def eval_ByteArrayQ(expr) -> bool:
+    """Return True if expr is a ByteArray atom."""
+    return isinstance(expr, ByteArray)
diff --git a/test/builtin/test_binary.py b/test/builtin/test_binary.py
index 0aebbb817..2fbcfbf70 100644
--- a/test/builtin/test_binary.py
+++ b/test/builtin/test_binary.py
@@ -1,7 +1,7 @@
 # -*- coding: utf-8 -*-
 
 import sys
-from test.helper import check_evaluation
+from test.helper import check_arg_counts, check_evaluation
 
 import pytest
 
@@ -456,3 +456,23 @@ def test_type_conversion():
     assert expr.value.dtype == np.int64
     expr = evaluate('NumericArray[{1,2}, "ComplexReal32"]')
     assert expr.value.dtype == np.complex64
+
+
+@pytest.mark.parametrize(
+    ("function_name", "msg_fragment"),
+    [
+        # FIXME: ToString in check_arg_counts() is giving a traceback
+        # for ByteArray[].
+        # (
+        #     "ByteArray",
+        #     "1 argument is",
+        # ),
+        (
+            "ByteArrayQ",
+            "1 argument is",
+        ),
+    ],
+)
+def test_arg_count_errors(function_name, msg_fragment):
+    """ """
+    check_arg_counts(function_name, msg_fragment)