diff --git a/tests/cli/test_main.py b/tests/cli/test_main.py
new file mode 100644
index 00000000..dfe8fe01
--- /dev/null
+++ b/tests/cli/test_main.py
@@ -0,0 +1,27 @@
+import pytest
+from cli.main import extract_content_string
+
+def test_extract_content_string_empty():
+    assert extract_content_string(None) is None
+    assert extract_content_string("") is None
+    assert extract_content_string("   ") is None
+
+def test_extract_content_string_valid_eval():
+    assert extract_content_string("[]") is None
+    assert extract_content_string("{}") is None
+    assert extract_content_string('""') is None
+
+def test_extract_content_string_invalid_eval_valueerror():
+    # simulating ValueError in literal_eval
+    assert extract_content_string("not_a_valid_python_literal") == "not_a_valid_python_literal"
+
+def test_extract_content_string_invalid_eval_syntaxerror():
+    # simulating SyntaxError in literal_eval
+    assert extract_content_string("{[}") == "{[}"
+
+def test_extract_content_string_dict():
+    assert extract_content_string({"text": "hello"}) == "hello"
+    assert extract_content_string({"text": "   "}) is None
+
+def test_extract_content_string_list():
+    assert extract_content_string([{"type": "text", "text": "hello"}, " world"]) == "hello world"