Use pytest.raises in test_lex

Makefile

@@ -46,7 +46,7 @@ tox: venv
 	tox
 
 flake:
-	flake8 hy tests --ignore=E121,E123,E126,E226,E24,E704,W503,E305
+	flake8 hy tests --ignore=E121,E123,E126,E226,E24,E704,W503,E302,E305,E701
 
 clear:
 	clear

tests/test_lex.py

@@ -5,56 +5,31 @@
 from hy.models import (HyExpression, HyInteger, HyFloat, HyComplex, HySymbol,
                        HyString, HyDict, HyList, HySet, HyCons)
 from hy.lex import LexException, PrematureEndOfInput, tokenize
+import pytest
+
+def peoi(): return pytest.raises(PrematureEndOfInput)
+def lexe(): return pytest.raises(LexException)
 
 
 def test_lex_exception():
     """ Ensure tokenize throws a fit on a partial input """
-    try:
-        tokenize("(foo")
-        assert True is False
-    except PrematureEndOfInput:
-        pass
-    try:
-        tokenize("{foo bar")
-        assert True is False
-    except PrematureEndOfInput:
-        pass
-    try:
-        tokenize("(defn foo [bar]")
-        assert True is False
-    except PrematureEndOfInput:
-        pass
-    try:
-        tokenize("(foo \"bar")
-        assert True is False
-    except PrematureEndOfInput:
-        pass
+    with peoi(): tokenize("(foo")
+    with peoi(): tokenize("{foo bar")
+    with peoi(): tokenize("(defn foo [bar]")
+    with peoi(): tokenize("(foo \"bar")
 
 
 def test_unbalanced_exception():
     """Ensure the tokenization fails on unbalanced expressions"""
-    try:
-        tokenize("(bar))")
-        assert True is False
-    except LexException:
-        pass
-
-    try:
-        tokenize("(baz [quux]])")
-        assert True is False
-    except LexException:
-        pass
+    with lexe(): tokenize("(bar))")
+    with lexe(): tokenize("(baz [quux]])")
 
 
 def test_lex_single_quote_err():
     "Ensure tokenizing \"' \" throws a LexException that can be stringified"
     # https://github.com/hylang/hy/issues/1252
-    try:
-        tokenize("' ")
-    except LexException as e:
-        assert "Could not identify the next token" in str(e)
-    else:
-        assert False
+    with lexe() as e: tokenize("' ")
+    assert "Could not identify the next token" in str(e.value)
 
 
 def test_lex_expression_symbols():