Convert the elliptic curve tests to be pytest-style (#576)

diff --git a/tests/util.py b/tests/util.py
index 7520a28..e1b8656 100644
--- a/tests/util.py
+++ b/tests/util.py
@@ -354,14 +354,14 @@
         An object compares equal to itself using the C{==} operator.
         """
         o = self.anInstance()
-        self.assertTrue(o == o)
+        assert (o == o)
 
     def test_identicalNe(self):
         """
         An object doesn't compare not equal to itself using the C{!=} operator.
         """
         o = self.anInstance()
-        self.assertFalse(o != o)
+        assert not (o != o)
 
     def test_sameEq(self):
         """
@@ -370,7 +370,7 @@
         """
         a = self.anInstance()
         b = self.anInstance()
-        self.assertTrue(a == b)
+        assert (a == b)
 
     def test_sameNe(self):
         """
@@ -379,7 +379,7 @@
         """
         a = self.anInstance()
         b = self.anInstance()
-        self.assertFalse(a != b)
+        assert not (a != b)
 
     def test_differentEq(self):
         """
@@ -388,7 +388,7 @@
         """
         a = self.anInstance()
         b = self.anotherInstance()
-        self.assertFalse(a == b)
+        assert not (a == b)
 
     def test_differentNe(self):
         """
@@ -397,7 +397,7 @@
         """
         a = self.anInstance()
         b = self.anotherInstance()
-        self.assertTrue(a != b)
+        assert (a != b)
 
     def test_anotherTypeEq(self):
         """
@@ -406,7 +406,7 @@
         """
         a = self.anInstance()
         b = object()
-        self.assertFalse(a == b)
+        assert not (a == b)
 
     def test_anotherTypeNe(self):
         """
@@ -415,7 +415,7 @@
         """
         a = self.anInstance()
         b = object()
-        self.assertTrue(a != b)
+        assert (a != b)
 
     def test_delegatedEq(self):
         """
@@ -429,7 +429,7 @@
 
         a = self.anInstance()
         b = Delegate()
-        self.assertEqual(a == b, [b])
+        assert (a == b) == [b]
 
     def test_delegateNe(self):
         """
@@ -443,7 +443,7 @@
 
         a = self.anInstance()
         b = Delegate()
-        self.assertEqual(a != b, [b])
+        assert (a != b) == [b]
 
 
 # The type name expected in warnings about using the wrong string type.