diff --git a/tests/test_parser.py b/tests/test_parser.py
new file mode 100644
index 0000000..25a0399
--- /dev/null
+++ b/tests/test_parser.py
@@ -0,0 +1,50 @@
+"""Tests for pattern detection module."""
+
+from cmdparse.patterns import detect_pattern_type
+
+
+class TestDetectPatternType:
+    def test_empty_input_returns_empty(self):
+        assert detect_pattern_type("") == "empty"
+        assert detect_pattern_type("   ") == "empty"
+        assert detect_pattern_type("\n\n") == "empty"
+
+    def test_table_detection(self):
+        table_input = """NAME    IMAGE    STATUS
+ nginx   nginx:1   running
+ redis   redis:3   stopped"""
+        result = detect_pattern_type(table_input)
+        assert result in ["table", "key_value_block"]
+
+    def test_key_value_colon_detection(self):
+        kv_input = """name: John
+ age: 30
+ city: NYC"""
+        result = detect_pattern_type(kv_input)
+        assert result == "key_value_colon"
+
+    def test_key_value_equals_detection(self):
+        kv_input = """name=John
+ age=30
+ city=NYC"""
+        result = detect_pattern_type(kv_input)
+        assert result == "key_value_equals"
+
+    def test_delimited_comma_detection(self):
+        csv_input = """name,age,city
+ John,30,NYC
+ Jane,25,LA"""
+        result = detect_pattern_type(csv_input)
+        assert result == "delimited_comma"
+
+    def test_delimited_tab_detection(self):
+        tsv_input = """name\tage\tcity
+ John\t30\tNYC"""
+        result = detect_pattern_type(tsv_input)
+        assert result == "delimited_tab"
+
+    def test_raw_text_detection(self):
+        raw_input = """This is just some random text
+ Without any particular structure"""
+        result = detect_pattern_type(raw_input)
+        assert result in ["raw", "table", "key_value_block"]