[lib][tests][latextools] Remove nose

IPython/lib/tests/test_latextools.py

@@ -5,7 +5,6 b''
 from contextlib import contextmanager
 from unittest.mock import patch
 
-import nose.tools as nt
 import pytest
 
 from IPython.lib import latextools
@@ -185,7 +184,13 b' def test_latex_to_png_invalid_hex_colors():'
     Test that invalid hex colors provided to dvipng gives an exception.
     """
     latex_string = "$x^2$"
-    nt.assert_raises(ValueError, lambda: latextools.latex_to_png(latex_string,
-                                        backend='dvipng', color="#f00bar"))
-    nt.assert_raises(ValueError, lambda: latextools.latex_to_png(latex_string,
-                                        backend='dvipng', color="#f00"))
+    pytest.raises(
+        ValueError,
+        lambda: latextools.latex_to_png(
+            latex_string, backend="dvipng", color="#f00bar"
+        ),
+    )
+    pytest.raises(
+        ValueError,
+        lambda: latextools.latex_to_png(latex_string, backend="dvipng", color="#f00"),
+    )