diff --git a/mathics/builtin/arithmetic.py b/mathics/builtin/arithmetic.py
index f52d69fcdb..536ee488bb 100644
--- a/mathics/builtin/arithmetic.py
+++ b/mathics/builtin/arithmetic.py
@@ -1876,9 +1876,9 @@ class Sum(_IterationFunction, SympyFunction):
     >> Sum[x ^ 2, {x, 1, y}] - y * (y + 1) * (2 * y + 1) / 6
      = 0
 
-    ## >> (-1 + a^n) Sum[a^(k n), {k, 0, m-1}] // Simplify
-    ## = -1 + (a ^ n) ^ m  # this is what I am getting
-    ## = Piecewise[{{m (-1 + a ^ n), a ^ n == 1}, {-1 + (a ^ n) ^ m, True}}]
+
+    >> (-1 + a^n) Sum[a^(k n), {k, 0, m-1}] // Simplify
+     = Piecewise[{{m (-1 + a ^ n), a ^ n == 1}, {-1 + (a ^ n) ^ m, True}}]
 
     Infinite sums:
     >> Sum[1 / 2 ^ i, {i, 1, Infinity}]
diff --git a/mathics/builtin/linalg.py b/mathics/builtin/linalg.py
index 3644c46d1f..1974e4849d 100644
--- a/mathics/builtin/linalg.py
+++ b/mathics/builtin/linalg.py
@@ -697,7 +697,7 @@ class Eigenvalues(Builtin):
 
     Symbolic eigenvalues:
     >> Eigenvalues[{{Cos[theta],Sin[theta],0},{-Sin[theta],Cos[theta],0},{0,0,1}}] // Sort
-     = {1, Cos[theta] + Sqrt[(-1 + Cos[theta]) (1 + Cos[theta])], Cos[theta] - Sqrt[(-1 + Cos[theta]) (1 + Cos[theta])]}
+     = {1, Cos[theta] + Sqrt[-1 + Cos[theta] ^ 2], Cos[theta] - Sqrt[-1 + Cos[theta] ^ 2]}
 
     >> Eigenvalues[{{7, 1}, {-4, 3}}]
      = {5, 5}
diff --git a/mathics/core/definitions.py b/mathics/core/definitions.py
index 36bcbe9437..a8c90c432b 100644
--- a/mathics/core/definitions.py
+++ b/mathics/core/definitions.py
@@ -382,8 +382,6 @@ def get_package_names(self) -> typing.List[str]:
         packages = [c.get_string_value() for c in packages.leaves]
         return packages
 
-        # return sorted({name.split("`")[0] for name in self.get_names()})
-
     def shorten_name(self, name_with_ctx) -> str:
         if "`" not in name_with_ctx:
             return name_with_ctx
diff --git a/mathics/session.py b/mathics/session.py
index fd338688fe..dc3b6147bb 100644
--- a/mathics/session.py
+++ b/mathics/session.py
@@ -26,5 +26,3 @@ def format_result(self, str_expression=None, timeout=None, form=None):
         if form is None:
             form = self.form
         return self.last_result.do_format(self.evaluation, form)
-
-
diff --git a/test/test_cellstotex.py b/test/test_cellstotex.py
new file mode 100644
index 0000000000..583eebf0ec
--- /dev/null
+++ b/test/test_cellstotex.py
@@ -0,0 +1,108 @@
+import os
+from mathics.core.parser import parse, MathicsSingleLineFeeder
+from mathics.core.definitions import Definitions
+from mathics.core.evaluation import Evaluation
+from mathics.core.expression import Symbol
+import pytest
+import urllib.request
+
+external_url = (
+    "https://raw.githubusercontent.com/jkuczm/MathematicaCellsToTeX/master/NoInstall.m"
+)
+
+pytestmark = pytest.mark.skipif(os.getenv("SKIP_CELLSTOTEX", None) is not None,
+                                reason="SKIP_CELLSTOTEX environment variable set")
+
+try:
+    http_code = urllib.request.urlopen(external_url).getcode()
+except:
+    url_reachable = False
+else:
+    url_reachable = http_code in (200,) # add other 2xx or 3xx's?
+
+definitions = Definitions(add_builtin=True)
+evaluation = Evaluation(definitions=definitions, catch_interrupt=False)
+set_versionnumber = 'Unprotect[$VersionNumber];$VersionNumber=11;Protect[$VersionNumber];'
+import_url = 'Import@"%s"' % external_url
+
+
+def _evaluate(str_expression):
+    expr = parse(definitions, MathicsSingleLineFeeder(str_expression))
+    return expr.evaluate(evaluation)
+
+_evaluate('LoadModule["pymathics.asy"]')
+
+def test_load():
+    str_expected1 = "{}"
+    message1 = ""
+    _evaluate(set_versionnumber)
+    result1 = _evaluate(import_url)
+    expected1 = _evaluate(str_expected1)
+
+
+    if message1:
+        assert result1 == expected1, message1
+    else:
+        assert result1 == expected1
+
+    result2 = _evaluate('Names["CellsToTeX`*"]')
+    expected2 = _evaluate('{"CellToTeX", "CellsToTeXException", "CellsToTeXPreamble"}')
+    print(result2)
+    assert result2 == expected2
+
+
+@pytest.mark.skipif(not url_reachable, reason="skipping since we can't reach %s" % external_url)
+#@pytest.mark.skip(
+#    reason="FIXME: full CellToTeX import test is not working yet: implement levelspec > 1"
+#)
+def test_load_and_run():
+    print("load and run")
+    str_expected0 = "None"
+    _evaluate(set_versionnumber)
+    result0 = _evaluate(import_url)
+    expected0 = _evaluate(str_expected0)
+
+    if result0 == Symbol("System`$Failed"):
+        return 0
+
+    str_expr1 = 'CellsToTeXPreamble[]'
+    str_expected1 = '"\\mmaSet{morefv={gobble=2,},}\\n"'
+    result1 = _evaluate(str_expr1)
+    expected1 = _evaluate(str_expected1)
+    assert result1 == expected1
+
+    str_expr1 = 'boxes=MakeBoxes[Pi];\
+                 cell = Cell[BoxData[boxes], "Input"];res=Catch[CellToTeX[cell, Style->"Input"]]'
+    str_expected1 = '"\\begin{mmaCell}{Input}\n  \\pi\n\\end{mmaCell}"'
+    message1 = ""
+    result1 = _evaluate(str_expr1)
+    expected1 = _evaluate(str_expected1)
+    if message1:
+        assert result1 == expected1, message1
+    else:
+        assert result1 == expected1
+
+    str_expr2 = 'boxes=MakeBoxes[(-b \\[PlusMinus] Sqrt[b^2-4*a*c])/(2 a)];\
+                 cell = Cell[BoxData[boxes],"Input"];res=Catch[CellToTeX[cell], Style->"Input"]'
+    str_expected2 = '"\\begin{mmaCell}{Input}\n  \\mmaFrac{-b\\(\\pmb{\\pm}\\)\\mmaSqrt{\\mmaSup{b}{2}-4 a c}}{2 a}\n\\end{mmaCell}"'
+    print(str_expr2)
+    message2 = ""
+    result2 = _evaluate(str_expr2)
+    expected2 = _evaluate(str_expected2)
+    if message2:
+        assert result2 == expected2, message2
+    else:
+        assert result2 == expected2
+
+    str_expr3 = 'boxes=MakeBoxes[Sqrt[Integrate[f[x],{x,a,b}]]];\
+                 cell = Cell[BoxData[boxes],"Input"];res=Catch[CellToTeX[cell]]'
+    print(str_expr3)
+
+    str_expected3 = '"\\begin{mmaCell}[morefunctionlocal={x}]{Input}\n  \\mmaSqrt{\\mmaSubSupM{\\int}{a}{b}f[x]dx}\n\\end{mmaCell}"'
+    message3 = ""
+    result3 = _evaluate(str_expr3)
+    expected3 = _evaluate(str_expected3)
+    if message3:
+        assert result3 == expected3, message3
+    else:
+        assert result3 == expected3