diff --git a/tests/test_utils.py b/tests/test_utils.py
index f74f8691e..d1ce86c94 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -161,3 +161,29 @@ def test_read_metadata(self, tmpdir):
         with pytest.raises(ValueError) as e_info:
             utils.read_metadata(meta_fn, as_data_frame=True)
         assert str(e_info.value) == "Duplicated strain in metadata: SEQ_1"
+
+    def test_myopen_text(self, tmpdir):
+        """Read a text file."""
+        path = str(tmpdir / 'test.txt')
+        with open(path, 'w') as f_write:
+            f_write.write('foo\nbar\n')
+        with utils.myopen(path) as f_read:
+            assert f_read.read() == 'foo\nbar\n'
+
+    def test_myopen_gzip(self, tmpdir):
+        """Read a text file compressed with gzip."""
+        import gzip
+        path = str(tmpdir / 'test.txt.gz')
+        with gzip.open(path, 'wt') as f_write:
+            f_write.write('foo\nbar\n')
+        with utils.myopen(path) as f_read:
+            assert f_read.read() == 'foo\nbar\n'
+
+    def test_myopen_lzma(self, tmpdir):
+        """Read a text file compressed with LZMA."""
+        import lzma
+        path = str(tmpdir / 'test.txt.xz')
+        with lzma.open(path, 'wt') as f_write:
+            f_write.write('foo\nbar\n')
+        with utils.myopen(path) as f_read:
+            assert f_read.read() == 'foo\nbar\n'