diff --git a/tests/test_report.py b/tests/test_report.py
index 0a5fd0b..1efce51 100644
--- a/tests/test_report.py
+++ b/tests/test_report.py
@@ -3,7 +3,29 @@
 """
 import pandas as pd
 
-from python_rap_demo.report import generate_markdown_report
+from python_rap_demo.report import format_month_section, generate_markdown_report
+
+
+def test_format_month_section():
+    # Define the variable month used in format_month_section
+    month = "January"
+    # Create the dataframe month_df used in format_month_section
+    month_df = pd.DataFrame({
+        "diagnosis": ["A", "B"],
+        "case_count": [10, 20],
+        "total": [20, 50],
+    })
+    # Calculate the prevalence rate
+    month_df["prevalence_rate"] = month_df["case_count"] / month_df["total"]
+    # Define the expected output of format_month_section
+    expected_output = (
+        "## Month: January\n"
+        "- A: 50.00% (10 cases)\n"
+        "- B: 40.00% (20 cases)\n"
+    )
+    result = format_month_section(month, month_df)
+    # Check that the output from format_month_section matches the expected output
+    assert result.strip() == expected_output.strip()
 
 
 def test_generate_markdown_report(tmp_path):