diff --git a/ecs/crm-datafetch/tests/writer/test_file_writer.py b/ecs/crm-datafetch/tests/writer/test_file_writer.py
index 6097d54b..cb6e748b 100644
--- a/ecs/crm-datafetch/tests/writer/test_file_writer.py
+++ b/ecs/crm-datafetch/tests/writer/test_file_writer.py
@@ -2,7 +2,35 @@ import os
 import textwrap
 
 import pytest
-from src.writer.file_writer import CsvWriter, JsonWriter
+from src.writer.file_writer import CsvWriter, FileWriter, JsonWriter
+
+
+class ConcreteFileWriter(FileWriter):
+    def write(self) -> str:
+        return super().write()
+
+
+class ConcreteFileWriterAbstractMethodNotImplemented(FileWriter):
+    pass
+
+
+class TestFileWriter:
+
+    def test_concrete_file_writer_instance_create(self):
+        concrete_file_writer = ConcreteFileWriter('', '')
+        assert isinstance(concrete_file_writer, FileWriter)
+
+    def test_concrete_file_writer_call_write_method(self):
+        concrete_file_writer = ConcreteFileWriter('', '')
+        concrete_file_writer.write()
+
+    def test_raise_abstract_class_do_not_create_instance(self):
+        with pytest.raises(TypeError):
+            FileWriter('', '')
+
+    def test_raise_concrete_file_writer_not_implemented_abstract_method(self):
+        with pytest.raises(TypeError):
+            ConcreteFileWriterAbstractMethodNotImplemented('', '')
 
 
 class TestJsonFileWriter: