Fix index out of range error when data not found

src/pypistats/__init__.py

@@ -124,6 +124,9 @@ def pypi_stats_api(
 
         _save_cache(cache_file, res)
 
+    if not res.get("data", []):
+        return f"The package '{res.get('package', '')}' does not exist"
+
     # Actual first and last dates of the fetched data
     first, last = _date_range(res["data"])
 

tests/test_pypistats.py

@@ -747,3 +747,22 @@ def test_format_pandas(self) -> None:
         # Assert
         assert isinstance(output, pandas.DataFrame)
         assert str(output).strip() == expected_output.strip()
+
+    @respx.mock
+    def test_package_not_exist(self) -> None:
+        # Arrange
+        package = "a" * 100
+        mocked_response = f"""{{
+            "data":[],
+            "package":"{package}",
+            "type":"python_major_downloads"
+        }}"""
+        mocked_url = f"https://pypistats.org/api/packages/{package}/python_major"
+        expected_output = f"The package '{package}' does not exist"
+
+        # Act
+        respx.get(mocked_url).respond(content=mocked_response)
+        output = pypistats.python_major(package)
+
+        # Assert
+        assert output == expected_output