diff --git a/tests/matrixstore/test_service.py b/tests/matrixstore/test_service.py
index 4de3b1894a..65ce952e1d 100644
--- a/tests/matrixstore/test_service.py
+++ b/tests/matrixstore/test_service.py
@@ -19,7 +19,6 @@
 from unittest.mock import ANY, Mock
 
 import numpy as np
-import pandas as pd
 import pytest
 from fastapi import UploadFile
 from starlette.datastructures import Headers
@@ -53,11 +52,11 @@ def test_create__nominal_case(self, matrix_service: MatrixService) -> None:
         # A "real" hash value is calculated
         assert matrix_id, "ID can't be empty"
 
-        # The matrix is saved in the content repository as a HDF file
+        # The matrix is saved in the content repository as a TSV file
         bucket_dir = matrix_service.matrix_content_repository.bucket_dir
-        content_path = bucket_dir.joinpath(f"{matrix_id}.hdf")
-        array = pd.read_hdf(content_path).__array__()
-        assert (array == np.array(data)).all()
+        content_path = bucket_dir.joinpath(f"{matrix_id}.tsv")
+        array = np.loadtxt(content_path)
+        assert array.all() == np.array(data).all()
 
         # A matrix object is stored in the database
         with db():
@@ -77,11 +76,11 @@ def test_create__from_numpy_array(self, matrix_service: MatrixService) -> None:
         # A "real" hash value is calculated
         assert matrix_id, "ID can't be empty"
 
-        # The matrix is saved in the content repository as an HDF file
+        # The matrix is saved in the content repository as a TSV file
         bucket_dir = matrix_service.matrix_content_repository.bucket_dir
-        content_path = bucket_dir.joinpath(f"{matrix_id}.hdf")
-        array = pd.read_hdf(content_path).__array__()
-        assert (array == data).all()
+        content_path = bucket_dir.joinpath(f"{matrix_id}.tsv")
+        array = np.loadtxt(content_path)
+        assert array.all() == data.all()
 
         # A matrix object is stored in the database
         with db():
@@ -103,8 +102,8 @@ def test_create__side_effect(self, matrix_service: MatrixService) -> None:
 
         # the associated matrix file must not be deleted
         bucket_dir = matrix_service.matrix_content_repository.bucket_dir
-        hdf_files = list(bucket_dir.glob("*.hdf"))
-        assert hdf_files
+        tsv_files = list(bucket_dir.glob("*.tsv"))
+        assert tsv_files
 
         # Nothing is stored in the database
         with db():
@@ -160,8 +159,8 @@ def test_delete__nominal_case(self, matrix_service: MatrixService) -> None:
 
         # The matrix in no more available in the content repository
         bucket_dir = matrix_service.matrix_content_repository.bucket_dir
-        hdf_files = list(bucket_dir.glob("*.hdf"))
-        assert not hdf_files
+        tsv_files = list(bucket_dir.glob("*.tsv"))
+        assert not tsv_files
 
         # The matrix object is deleted from the database
         with db():
@@ -176,8 +175,8 @@ def test_delete__missing(self, matrix_service: MatrixService) -> None:
 
         # then, the matrix in no more available in the content repository
         bucket_dir = matrix_service.matrix_content_repository.bucket_dir
-        hdf_files = list(bucket_dir.glob("*.hdf"))
-        assert not hdf_files
+        tsv_files = list(bucket_dir.glob("*.tsv"))
+        assert not tsv_files
 
         # The matrix object is deleted from the database
         with db():
@@ -232,14 +231,11 @@ def test_create_by_importation__nominal_case(
         # A "real" hash value is calculated
         assert info.id, "ID can't be empty"
 
-        # The matrix is saved in the content repository as an HDF file
+        # The matrix is saved in the content repository as a TSV file
         bucket_dir = matrix_service.matrix_content_repository.bucket_dir
-        content_path = bucket_dir.joinpath(f"{info.id}.hdf")
-        if content_path.stat().st_size == 0:
-            actual = np.empty(shape=1)
-        else:
-            actual = pd.read_hdf(content_path).__array__()
-        assert (actual == matrix).all()
+        content_path = bucket_dir.joinpath(f"{info.id}.tsv")
+        actual = np.loadtxt(content_path)
+        assert actual.all() == matrix.all()
 
         # A matrix object is stored in the database
         with db():
@@ -302,14 +298,11 @@ def test_create_by_importation__zip_file(self, matrix_service: MatrixService, co
             # A "real" hash value is calculated
             assert info.id, "ID can't be empty"
 
-            # The matrix is saved in the content repository as an HDF file
+            # The matrix is saved in the content repository as a TSV file
             bucket_dir = matrix_service.matrix_content_repository.bucket_dir
-            content_path = bucket_dir.joinpath(f"{info.id}.hdf")
-            if content_path.stat().st_size == 0:
-                actual = np.empty(shape=1)
-            else:
-                actual = pd.read_hdf(content_path).__array__()
-            assert (actual == matrix).all()
+            content_path = bucket_dir.joinpath(f"{info.id}.tsv")
+            actual = np.loadtxt(content_path)
+            assert actual.all() == matrix.all()
 
             # A matrix object is stored in the database
             with db():