style: use Black everywhere (#2594)

* style: use Black everywhere

* style: minor touchup from review

tests/test_iostream.py

@@ -18,6 +18,7 @@ try:
     # Python 3.4
     from contextlib import redirect_stdout
 except ImportError:
+
     @contextmanager
     def redirect_stdout(target):
         original = sys.stdout
@@ -25,10 +26,12 @@ except ImportError:
         yield
         sys.stdout = original
 
+
 try:
     # Python 3.5
     from contextlib import redirect_stderr
 except ImportError:
+
     @contextmanager
     def redirect_stderr(target):
         original = sys.stderr
@@ -42,16 +45,16 @@ def test_captured(capsys):
     m.captured_output(msg)
     stdout, stderr = capsys.readouterr()
     assert stdout == msg
-    assert stderr == ''
+    assert stderr == ""
 
     m.captured_output_default(msg)
     stdout, stderr = capsys.readouterr()
     assert stdout == msg
-    assert stderr == ''
+    assert stderr == ""
 
     m.captured_err(msg)
     stdout, stderr = capsys.readouterr()
-    assert stdout == ''
+    assert stdout == ""
     assert stderr == msg
 
 
@@ -63,7 +66,7 @@ def test_captured_large_string(capsys):
     m.captured_output_default(msg)
     stdout, stderr = capsys.readouterr()
     assert stdout == msg
-    assert stderr == ''
+    assert stderr == ""
 
 
 def test_guard_capture(capsys):
@@ -71,7 +74,7 @@ def test_guard_capture(capsys):
     m.guard_output(msg)
     stdout, stderr = capsys.readouterr()
     assert stdout == msg
-    assert stderr == ''
+    assert stderr == ""
 
 
 def test_series_captured(capture):
@@ -88,7 +91,7 @@ def test_flush(capfd):
     with m.ostream_redirect():
         m.noisy_function(msg, flush=False)
         stdout, stderr = capfd.readouterr()
-        assert stdout == ''
+        assert stdout == ""
 
         m.noisy_function(msg2, flush=True)
         stdout, stderr = capfd.readouterr()
@@ -107,15 +110,15 @@ def test_not_captured(capfd):
         m.raw_output(msg)
     stdout, stderr = capfd.readouterr()
     assert stdout == msg
-    assert stderr == ''
-    assert stream.getvalue() == ''
+    assert stderr == ""
+    assert stream.getvalue() == ""
 
     stream = StringIO()
     with redirect_stdout(stream):
         m.captured_output(msg)
     stdout, stderr = capfd.readouterr()
-    assert stdout == ''
-    assert stderr == ''
+    assert stdout == ""
+    assert stderr == ""
     assert stream.getvalue() == msg
 
 
@@ -125,16 +128,16 @@ def test_err(capfd):
     with redirect_stderr(stream):
         m.raw_err(msg)
     stdout, stderr = capfd.readouterr()
-    assert stdout == ''
+    assert stdout == ""
     assert stderr == msg
-    assert stream.getvalue() == ''
+    assert stream.getvalue() == ""
 
     stream = StringIO()
     with redirect_stderr(stream):
         m.captured_err(msg)
     stdout, stderr = capfd.readouterr()
-    assert stdout == ''
-    assert stderr == ''
+    assert stdout == ""
+    assert stderr == ""
     assert stream.getvalue() == msg
 
 
@@ -146,8 +149,8 @@ def test_multi_captured(capfd):
         m.captured_output("c")
         m.raw_output("d")
     stdout, stderr = capfd.readouterr()
-    assert stdout == 'bd'
-    assert stream.getvalue() == 'ac'
+    assert stdout == "bd"
+    assert stream.getvalue() == "ac"
 
 
 def test_dual(capsys):
@@ -164,14 +167,14 @@ def test_redirect(capfd):
         m.raw_output(msg)
     stdout, stderr = capfd.readouterr()
     assert stdout == msg
-    assert stream.getvalue() == ''
+    assert stream.getvalue() == ""
 
     stream = StringIO()
     with redirect_stdout(stream):
         with m.ostream_redirect():
             m.raw_output(msg)
     stdout, stderr = capfd.readouterr()
-    assert stdout == ''
+    assert stdout == ""
     assert stream.getvalue() == msg
 
     stream = StringIO()
@@ -179,7 +182,7 @@ def test_redirect(capfd):
         m.raw_output(msg)
     stdout, stderr = capfd.readouterr()
     assert stdout == msg
-    assert stream.getvalue() == ''
+    assert stream.getvalue() == ""
 
 
 def test_redirect_err(capfd):
@@ -193,7 +196,7 @@ def test_redirect_err(capfd):
             m.raw_err(msg2)
     stdout, stderr = capfd.readouterr()
     assert stdout == msg
-    assert stderr == ''
+    assert stderr == ""
     assert stream.getvalue() == msg2
 
 
@@ -209,7 +212,7 @@ def test_redirect_both(capfd):
                 m.raw_output(msg)
                 m.raw_err(msg2)
     stdout, stderr = capfd.readouterr()
-    assert stdout == ''
-    assert stderr == ''
+    assert stdout == ""
+    assert stderr == ""
     assert stream.getvalue() == msg
     assert stream2.getvalue() == msg2