diff --git a/doc/en/tmpdir.rst b/doc/en/tmpdir.rst
index 330011bb3..01397a5ba 100644
--- a/doc/en/tmpdir.rst
+++ b/doc/en/tmpdir.rst
@@ -22,7 +22,7 @@ created in the `base temporary directory`_.
     # content of test_tmp_path.py
     import os
 
-    CONTENT = u"content"
+    CONTENT = "content"
 
 
     def test_create_file(tmp_path):
diff --git a/src/_pytest/assertion/rewrite.py b/src/_pytest/assertion/rewrite.py
index ac9b85e67..ce698f368 100644
--- a/src/_pytest/assertion/rewrite.py
+++ b/src/_pytest/assertion/rewrite.py
@@ -6,7 +6,6 @@ import itertools
 import marshal
 import os
 import re
-import string
 import struct
 import sys
 import types
@@ -336,8 +335,8 @@ def _write_pyc(state, co, source_stat, pyc):
     return True
 
 
-RN = "\r\n".encode()
-N = "\n".encode()
+RN = b"\r\n"
+N = b"\n"
 
 cookie_re = re.compile(r"^[ \t\f]*#.*coding[:=][ \t]*[-\w.]+")
 BOM_UTF8 = "\xef\xbb\xbf"
@@ -420,15 +419,7 @@ def _saferepr(obj):
     JSON reprs.
 
     """
-    r = saferepr(obj)
-    # only occurs in python2.x, repr must return text in python3+
-    if isinstance(r, bytes):
-        # Represent unprintable bytes as `\x##`
-        r = "".join(
-            "\\x{:x}".format(ord(c)) if c not in string.printable else c.decode()
-            for c in r
-        )
-    return r.replace("\n", "\\n")
+    return saferepr(obj).replace("\n", "\\n")
 
 
 def _format_assertmsg(obj):
@@ -448,9 +439,6 @@ def _format_assertmsg(obj):
         obj = saferepr(obj)
         replaces.append(("\\n", "\n~"))
 
-    if isinstance(obj, bytes):
-        replaces = [(r1.encode(), r2.encode()) for r1, r2 in replaces]
-
     for r1, r2 in replaces:
         obj = obj.replace(r1, r2)
 
diff --git a/src/_pytest/assertion/util.py b/src/_pytest/assertion/util.py
index 2be759bac..9d6af5d69 100644
--- a/src/_pytest/assertion/util.py
+++ b/src/_pytest/assertion/util.py
@@ -13,15 +13,6 @@ from _pytest._io.saferepr import saferepr
 _reprcompare = None
 
 
-# the re-encoding is needed for python2 repr
-# with non-ascii characters (see issue 877 and 1379)
-def ecu(s):
-    if isinstance(s, bytes):
-        return s.decode("UTF-8", "replace")
-    else:
-        return s
-
-
 def format_explanation(explanation):
     """This formats an explanation
 
@@ -32,7 +23,7 @@ def format_explanation(explanation):
     for when one explanation needs to span multiple lines, e.g. when
     displaying diffs.
     """
-    explanation = ecu(explanation)
+    explanation = explanation
     lines = _split_explanation(explanation)
     result = _format_lines(lines)
     return "\n".join(result)
@@ -135,7 +126,7 @@ def assertrepr_compare(config, op, left, right):
     left_repr = saferepr(left, maxsize=int(width // 2))
     right_repr = saferepr(right, maxsize=width - len(left_repr))
 
-    summary = "{} {} {}".format(ecu(left_repr), op, ecu(right_repr))
+    summary = "{} {} {}".format(left_repr, op, right_repr)
 
     verbose = config.getoption("verbose")
     explanation = None
diff --git a/src/_pytest/compat.py b/src/_pytest/compat.py
index a4f3bc003..6f1275e61 100644
--- a/src/_pytest/compat.py
+++ b/src/_pytest/compat.py
@@ -170,7 +170,7 @@ def ascii_escaped(val):
     """If val is pure ascii, returns it as a str().  Otherwise, escapes
     bytes objects into a sequence of escaped bytes:
 
-    b'\xc3\xb4\xc5\xd6' -> u'\\xc3\\xb4\\xc5\\xd6'
+    b'\xc3\xb4\xc5\xd6' -> '\\xc3\\xb4\\xc5\\xd6'
 
     and escapes unicode objects into a sequence of escaped unicode
     ids, e.g.:
diff --git a/src/_pytest/pathlib.py b/src/_pytest/pathlib.py
index 09b1bb3d5..3269c25ed 100644
--- a/src/_pytest/pathlib.py
+++ b/src/_pytest/pathlib.py
@@ -134,9 +134,7 @@ def create_cleanup_lock(p):
             raise
     else:
         pid = os.getpid()
-        spid = str(pid)
-        if not isinstance(spid, bytes):
-            spid = spid.encode("ascii")
+        spid = str(pid).encode()
         os.write(fd, spid)
         os.close(fd)
         if not lock_path.is_file():
diff --git a/testing/acceptance_test.py b/testing/acceptance_test.py
index 9d903f802..caa0d5191 100644
--- a/testing/acceptance_test.py
+++ b/testing/acceptance_test.py
@@ -510,7 +510,7 @@ class TestGeneralUsage:
             """\
             import pytest
 
-            @pytest.mark.parametrize("data", [b"\\x00", "\\x00", u'ação'])
+            @pytest.mark.parametrize("data", [b"\\x00", "\\x00", 'ação'])
             def test_foo(data):
                 assert data
             """
@@ -998,16 +998,8 @@ def test_zipimport_hook(testdir, tmpdir):
 
 def test_import_plugin_unicode_name(testdir):
     testdir.makepyfile(myplugin="")
-    testdir.makepyfile(
-        """
-        def test(): pass
-    """
-    )
-    testdir.makeconftest(
-        """
-        pytest_plugins = [u'myplugin']
-    """
-    )
+    testdir.makepyfile("def test(): pass")
+    testdir.makeconftest("pytest_plugins = ['myplugin']")
     r = testdir.runpytest()
     assert r.ret == 0
 
diff --git a/testing/code/test_source.py b/testing/code/test_source.py
index a12a102a0..15e0bf24a 100644
--- a/testing/code/test_source.py
+++ b/testing/code/test_source.py
@@ -28,7 +28,7 @@ def test_source_str_function():
 def test_unicode():
     x = Source("4")
     assert str(x) == "4"
-    co = _pytest._code.compile('u"å"', mode="eval")
+    co = _pytest._code.compile('"å"', mode="eval")
     val = eval(co)
     assert isinstance(val, str)
 
diff --git a/testing/python/collect.py b/testing/python/collect.py
index 981e30fc3..d648452fd 100644
--- a/testing/python/collect.py
+++ b/testing/python/collect.py
@@ -116,7 +116,7 @@ class TestModule:
         """Check test modules collected which raise ImportError with unicode messages
         are handled properly (#2336).
         """
-        testdir.makepyfile("raise ImportError(u'Something bad happened ☺')")
+        testdir.makepyfile("raise ImportError('Something bad happened ☺')")
         result = testdir.runpytest()
         result.stdout.fnmatch_lines(
             [
diff --git a/testing/test_assertion.py b/testing/test_assertion.py
index e651c09ce..eced5461a 100644
--- a/testing/test_assertion.py
+++ b/testing/test_assertion.py
@@ -1219,7 +1219,7 @@ def test_assert_with_unicode(monkeypatch, testdir):
     testdir.makepyfile(
         """\
         def test_unicode():
-            assert u'유니코드' == u'Unicode'
+            assert '유니코드' == 'Unicode'
         """
     )
     result = testdir.runpytest()
diff --git a/testing/test_capture.py b/testing/test_capture.py
index 0825745ad..a85025c27 100644
--- a/testing/test_capture.py
+++ b/testing/test_capture.py
@@ -111,10 +111,10 @@ def test_capturing_unicode(testdir, method):
 @pytest.mark.parametrize("method", ["fd", "sys"])
 def test_capturing_bytes_in_utf8_encoding(testdir, method):
     testdir.makepyfile(
-        """
+        """\
         def test_unicode():
             print('b\\u00f6y')
-    """
+        """
     )
     result = testdir.runpytest("--capture=%s" % method)
     result.stdout.fnmatch_lines(["*1 passed*"])
@@ -511,7 +511,7 @@ class TestCaptureFixture:
             """\
             def test_hello(capfd):
                 import os
-                os.write(1, "42".encode('ascii'))
+                os.write(1, b"42")
                 out, err = capfd.readouterr()
                 assert out.startswith("42")
                 capfd.close()
@@ -564,7 +564,7 @@ class TestCaptureFixture:
             """\
             def test_hello(capfd):
                 import os
-                os.write(1, str(42).encode('ascii'))
+                os.write(1, b'42')
                 raise KeyboardInterrupt()
             """
         )
@@ -1136,12 +1136,12 @@ class TestStdCaptureFD(TestStdCapture):
 
     def test_simple_only_fd(self, testdir):
         testdir.makepyfile(
-            """
+            """\
             import os
             def test_x():
-                os.write(1, "hello\\n".encode("ascii"))
+                os.write(1, b"hello\\n")
                 assert 0
-        """
+            """
         )
         result = testdir.runpytest_subprocess()
         result.stdout.fnmatch_lines(
diff --git a/testing/test_doctest.py b/testing/test_doctest.py
index 65c8cf366..bf0405546 100644
--- a/testing/test_doctest.py
+++ b/testing/test_doctest.py
@@ -153,7 +153,7 @@ class TestDoctests:
             )
         )
         doctest = """
-            >>> u"{}"
+            >>> "{}"
             {}
         """.format(
             test_string, repr(test_string)
@@ -671,7 +671,7 @@ class TestDoctests:
             test_print_unicode_value=r"""
             Here is a doctest::
 
-                >>> print(u'\xE5\xE9\xEE\xF8\xFC')
+                >>> print('\xE5\xE9\xEE\xF8\xFC')
                 åéîøü
         """
         )
diff --git a/testing/test_junitxml.py b/testing/test_junitxml.py
index 69b9c09c3..bcf83b352 100644
--- a/testing/test_junitxml.py
+++ b/testing/test_junitxml.py
@@ -873,12 +873,12 @@ def test_logxml_check_isdir(testdir):
 
 def test_escaped_parametrized_names_xml(testdir):
     testdir.makepyfile(
-        """
+        """\
         import pytest
-        @pytest.mark.parametrize('char', [u"\\x00"])
+        @pytest.mark.parametrize('char', ["\\x00"])
         def test_func(char):
             assert char
-    """
+        """
     )
     result, dom = runandparse(testdir)
     assert result.ret == 0
diff --git a/testing/test_nose.py b/testing/test_nose.py
index 8a3ce6454..f60c3af53 100644
--- a/testing/test_nose.py
+++ b/testing/test_nose.py
@@ -370,7 +370,7 @@ def test_skip_test_with_unicode(testdir):
         import unittest
         class TestClass():
             def test_io(self):
-                raise unittest.SkipTest(u'😊')
+                raise unittest.SkipTest('😊')
         """
     )
     result = testdir.runpytest()
diff --git a/testing/test_pytester.py b/testing/test_pytester.py
index 82ff37c13..96bf85040 100644
--- a/testing/test_pytester.py
+++ b/testing/test_pytester.py
@@ -201,12 +201,10 @@ def test_makepyfile_utf8(testdir):
     """Ensure makepyfile accepts utf-8 bytes as input (#2738)"""
     utf8_contents = """
         def setup_function(function):
-            mixed_encoding = u'São Paulo'
-    """.encode(
-        "utf-8"
-    )
+            mixed_encoding = 'São Paulo'
+    """.encode()
     p = testdir.makepyfile(utf8_contents)
-    assert "mixed_encoding = u'São Paulo'".encode() in p.read("rb")
+    assert "mixed_encoding = 'São Paulo'".encode() in p.read("rb")
 
 
 class TestInlineRunModulesCleanup:
diff --git a/testing/test_runner.py b/testing/test_runner.py
index 77fdcecc3..13f722036 100644
--- a/testing/test_runner.py
+++ b/testing/test_runner.py
@@ -632,8 +632,7 @@ def test_pytest_fail_notrace_collection(testdir):
     assert "def some_internal_function()" not in result.stdout.str()
 
 
-@pytest.mark.parametrize("str_prefix", ["u", ""])
-def test_pytest_fail_notrace_non_ascii(testdir, str_prefix):
+def test_pytest_fail_notrace_non_ascii(testdir):
     """Fix pytest.fail with pytrace=False with non-ascii characters (#1178).
 
     This tests with native and unicode strings containing non-ascii chars.
@@ -643,9 +642,8 @@ def test_pytest_fail_notrace_non_ascii(testdir, str_prefix):
         import pytest
 
         def test_hello():
-            pytest.fail(%s'oh oh: ☺', pytrace=False)
+            pytest.fail('oh oh: ☺', pytrace=False)
         """
-        % str_prefix
     )
     result = testdir.runpytest()
     result.stdout.fnmatch_lines(["*test_hello*", "oh oh: ☺"])
@@ -790,7 +788,7 @@ def test_unicode_in_longrepr(testdir):
             outcome = yield
             rep = outcome.get_result()
             if rep.when == "call":
-                rep.longrepr = u'ä'
+                rep.longrepr = 'ä'
         """
     )
     testdir.makepyfile(
diff --git a/testing/test_terminal.py b/testing/test_terminal.py
index f53cb6837..cc2c474ab 100644
--- a/testing/test_terminal.py
+++ b/testing/test_terminal.py
@@ -1672,7 +1672,6 @@ def test_line_with_reprcrash(monkeypatch):
     check("😄😄😄😄😄\n2nd line", 29, "FAILED some::nodeid - 😄😄...")
 
     # NOTE: constructed, not sure if this is supported.
-    # It would fail if not using u"" in Python 2 for mocked_pos.
     mocked_pos = "nodeid::😄::withunicode"
     check("😄😄😄😄😄\n2nd line", 29, "FAILED nodeid::😄::withunicode")
     check("😄😄😄😄😄\n2nd line", 40, "FAILED nodeid::😄::withunicode - 😄😄...")
diff --git a/testing/test_warnings.py b/testing/test_warnings.py
index 165402478..08a368521 100644
--- a/testing/test_warnings.py
+++ b/testing/test_warnings.py
@@ -130,7 +130,7 @@ def test_unicode(testdir, pyfile_with_warnings):
 
         @pytest.fixture
         def fix():
-            warnings.warn(u"测试")
+            warnings.warn("测试")
             yield
 
         def test_func(fix):
@@ -207,13 +207,13 @@ def test_filterwarnings_mark(testdir, default_config):
 def test_non_string_warning_argument(testdir):
     """Non-str argument passed to warning breaks pytest (#2956)"""
     testdir.makepyfile(
-        """
+        """\
         import warnings
         import pytest
 
         def test():
-            warnings.warn(UserWarning(1, u'foo'))
-    """
+            warnings.warn(UserWarning(1, 'foo'))
+        """
     )
     result = testdir.runpytest("-W", "always")
     result.stdout.fnmatch_lines(["*= 1 passed, 1 warnings in *"])