diff --git a/tests/unit/utils/test_is_number.py b/tests/unit/utils/test_is_number.py
new file mode 100644
index 0000000..6785f2c
--- /dev/null
+++ b/tests/unit/utils/test_is_number.py
@@ -0,0 +1,41 @@
+from src.jeb_utils.utils import is_number
+import pytest
+
+@pytest.mark.parametrize('string,base,expected', [
+    # Valid
+    ('7', 8, True),
+    ('0', 8, True),
+    ('0', 36, True),
+    ('0', 2, True),
+    ('0', 10, True),
+    ('1', 10, True),
+    ('0a', 11, True),
+    ('helloworld', 36, True),
+    ('helloworld', 35, True),
+    ('helloworld', 34, True),
+    ('helloworld', 33, True),
+
+
+    # Invalid
+
+    # Invalid numbers
+    ('', 10, False),
+    ('a', 10, False),
+    ('1a', 10, False),
+    ('0a', 10, False),
+    ('0a', 8, False),
+    ('helloworld', 32, False),
+    ('9', 8, False),
+    ('8', 8, False),
+
+    # Invalid bases
+    ('0', 37, False),
+    ('0', 1, False),
+    ('1', 1, False),
+    ('2', 1, False),
+    ('0', 0, False),
+    ('1', 0, False),
+    ('2', 0, False),
+])
+def test_is_number(string, base, expected):
+    assert is_number(string, base) == expected
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