diff --git a/tests/test_album.py b/tests/test_album.py
index 2c7f369..a44305b 100755
--- a/tests/test_album.py
+++ b/tests/test_album.py
@@ -107,8 +107,8 @@ class TestPyLastAlbum(PyLastTestCase):
         image = album.get_cover_image()
 
         # Assert
-        self.assertTrue(image.startswith("https://"))
-        self.assertTrue(image.endswith(".png"))
+        self.assert_startswith(image, "https://")
+        self.assert_endswith(image, ".png")
 
 
 if __name__ == '__main__':
diff --git a/tests/test_library.py b/tests/test_library.py
index 1e437f1..ca87c8e 100755
--- a/tests/test_library.py
+++ b/tests/test_library.py
@@ -19,7 +19,7 @@ class TestPyLastLibrary(PyLastTestCase):
         representation = repr(library)
 
         # Assert
-        self.assertTrue(representation.startswith("pylast.Library("))
+        self.assert_startswith(representation, "pylast.Library(")
 
     def test_str(self):
         # Arrange
@@ -29,7 +29,7 @@ class TestPyLastLibrary(PyLastTestCase):
         string = str(library)
 
         # Assert
-        self.assertTrue(string.endswith("'s Library"))
+        self.assert_endswith(string, "'s Library")
 
     def test_library_is_hashable(self):
         # Arrange
diff --git a/tests/test_librefm.py b/tests/test_librefm.py
index 7c958cb..ab3ea3f 100755
--- a/tests/test_librefm.py
+++ b/tests/test_librefm.py
@@ -42,7 +42,7 @@ class TestPyLastWithLibreFm(unittest.TestCase):
         representation = repr(network)
 
         # Assert
-        self.assertTrue(representation.startswith("pylast.LibreFMNetwork("))
+        self.assert_startswith(representation, "pylast.LibreFMNetwork(")
 
 
 if __name__ == '__main__':
diff --git a/tests/test_network.py b/tests/test_network.py
index e1896ea..e41a9fc 100755
--- a/tests/test_network.py
+++ b/tests/test_network.py
@@ -327,12 +327,12 @@ class TestPyLastNetwork(PyLastTestCase):
         # Assert
         self.assertEqual(len(images), 4)
 
-        self.assertTrue(images[pylast.SIZE_SMALL].startswith("https://"))
-        self.assertTrue(images[pylast.SIZE_SMALL].endswith(".png"))
+        self.assert_startswith(images[pylast.SIZE_SMALL], "https://")
+        self.assert_endswith(images[pylast.SIZE_SMALL], ".png")
         self.assertIn("/34s/", images[pylast.SIZE_SMALL])
 
-        self.assertTrue(images[pylast.SIZE_EXTRA_LARGE].startswith("https://"))
-        self.assertTrue(images[pylast.SIZE_EXTRA_LARGE].endswith(".png"))
+        self.assert_startswith(images[pylast.SIZE_EXTRA_LARGE], "https://")
+        self.assert_endswith(images[pylast.SIZE_EXTRA_LARGE], ".png")
         self.assertIn("/300x300/", images[pylast.SIZE_EXTRA_LARGE])
 
     def test_artist_search(self):
@@ -359,12 +359,12 @@ class TestPyLastNetwork(PyLastTestCase):
         # Assert
         self.assertEqual(len(images), 5)
 
-        self.assertTrue(images[pylast.SIZE_SMALL].startswith("https://"))
-        self.assertTrue(images[pylast.SIZE_SMALL].endswith(".png"))
+        self.assert_startswith(images[pylast.SIZE_SMALL], "https://")
+        self.assert_endswith(images[pylast.SIZE_SMALL], ".png")
         self.assertIn("/34s/", images[pylast.SIZE_SMALL])
 
-        self.assertTrue(images[pylast.SIZE_EXTRA_LARGE].startswith("https://"))
-        self.assertTrue(images[pylast.SIZE_EXTRA_LARGE].endswith(".png"))
+        self.assert_startswith(images[pylast.SIZE_EXTRA_LARGE], "https://")
+        self.assert_endswith(images[pylast.SIZE_EXTRA_LARGE], ".png")
         self.assertIn("/300x300/", images[pylast.SIZE_EXTRA_LARGE])
 
     def test_track_search(self):
diff --git a/tests/test_pylast.py b/tests/test_pylast.py
index 9ebbcc1..c09ad27 100755
--- a/tests/test_pylast.py
+++ b/tests/test_pylast.py
@@ -52,6 +52,12 @@ class PyLastTestCase(unittest.TestCase):
             api_key=API_KEY, api_secret=API_SECRET,
             username=self.username, password_hash=password_hash)
 
+    def assert_startswith(self, str, prefix, start=None, end=None):
+        self.assertTrue(str.startswith(prefix, start, end))
+
+    def assert_endswith(self, str, suffix, start=None, end=None):
+        self.assertTrue(str.endswith(suffix, start, end))
+
     def helper_is_thing_hashable(self, thing):
         # Arrange
         things = set()
diff --git a/tests/test_user.py b/tests/test_user.py
index c742bd3..ecb7c94 100755
--- a/tests/test_user.py
+++ b/tests/test_user.py
@@ -20,7 +20,7 @@ class TestPyLastUser(PyLastTestCase):
         representation = repr(user)
 
         # Assert
-        self.assertTrue(representation.startswith("pylast.User('RJ',"))
+        self.assert_startswith(representation, "pylast.User('RJ',")
 
     def test_str(self):
         # Arrange
@@ -342,7 +342,7 @@ class TestPyLastUser(PyLastTestCase):
         url = user.get_image()
 
         # Assert
-        self.assertTrue(url.startswith("https://"))
+        self.assert_startswith(url, "https://")
 
     def test_user_get_library(self):
         # Arrange
@@ -392,8 +392,8 @@ class TestPyLastUser(PyLastTestCase):
         image = user.get_image()
 
         # Assert
-        self.assertTrue(image.startswith("https://"))
-        self.assertTrue(image.endswith(".png"))
+        self.assert_startswith(image, "https://")
+        self.assert_endswith(image, ".png")
 
     def test_get_url(self):
         # Arrange