refactor: drop PY3 and failfast

tests/conftest.py

@@ -208,17 +208,9 @@ def pytest_configure():
 
     # Provide simple `six`-like aliases.
     pytest.PY2 = (sys.version_info.major == 2)
-    pytest.PY3 = (sys.version_info.major == 3)
     pytest.CPYTHON = (platform.python_implementation() == "CPython")
     pytest.PYPY = (platform.python_implementation() == "PyPy")
 
-    if not pytest.PY2 and not pytest.PY3:
-        print("pybind11 is only supported on Python 2.x or 3.x")
-        sys.exit(1)
-    if not pytest.CPYTHON and not pytest.PYPY:
-        print("pybind11 is only supported for CPython or PyPy")
-        sys.exit(1)
-
     skipif = pytest.mark.skipif
     pytest.suppress = suppress
     pytest.requires_numpy = skipif(not np, reason="numpy is not installed")
@@ -229,7 +221,7 @@ def pytest_configure():
         not have_eigen or not scipy, reason="eigen and/or scipy are not installed")
     pytest.unsupported_on_pypy = skipif(pytest.PYPY, reason="unsupported on PyPy")
     pytest.bug_in_pypy = pytest.mark.xfail(pytest.PYPY, reason="bug in PyPy")
-    pytest.unsupported_on_pypy3 = skipif(pytest.PYPY and pytest.PY3,
+    pytest.unsupported_on_pypy3 = skipif(pytest.PYPY and not pytest.PY2,
                                          reason="unsupported on PyPy3")
     pytest.unsupported_on_pypy_lt_6 = skipif(pytest.PYPY and sys.pypy_version_info[0] < 6,
                                              reason="unsupported on PyPy<6")

tests/test_buffers.py

@@ -95,22 +95,22 @@ def test_pointer_to_member_fn():
 def test_readonly_buffer():
     buf = m.BufferReadOnly(0x64)
     view = memoryview(buf)
-    assert view[0] == 0x64 if pytest.PY3 else b'd'
+    assert view[0] == b'd' if pytest.PY2 else 0x64
     assert view.readonly
 
 
 @pytest.unsupported_on_pypy
 def test_selective_readonly_buffer():
     buf = m.BufferReadOnlySelect()
 
-    memoryview(buf)[0] = 0x64 if pytest.PY3 else b'd'
+    memoryview(buf)[0] = b'd' if pytest.PY2 else 0x64
     assert buf.value == 0x64
 
     io.BytesIO(b'A').readinto(buf)
     assert buf.value == ord(b'A')
 
     buf.readonly = True
     with pytest.raises(TypeError):
-        memoryview(buf)[0] = 0 if pytest.PY3 else b'\0'
+        memoryview(buf)[0] = b'\0' if pytest.PY2 else 0
     with pytest.raises(TypeError):
         io.BytesIO(b'1').readinto(buf)

tests/test_pytypes.py

@@ -113,7 +113,7 @@ def test_bytes(doc):
     assert m.bytes_from_str().decode() == "bar"
 
     assert doc(m.bytes_from_str) == "bytes_from_str() -> {}".format(
-        "bytes" if pytest.PY3 else "str"
+        "str" if pytest.PY2 else "bytes"
     )
 
 
@@ -292,7 +292,7 @@ def test_memoryview(method, args, fmt, expected_view):
     view = method(*args)
     assert isinstance(view, memoryview)
     assert view.format == fmt
-    if isinstance(expected_view, bytes) or pytest.PY3:
+    if isinstance(expected_view, bytes) or not pytest.PY2:
         view_as_list = list(view)
     else:
         # Using max to pick non-zero byte (big-endian vs little-endian).

tests/test_stl_binders.py

@@ -76,7 +76,7 @@ def test_vector_buffer():
     assert v[1] == 2
     v[2] = 5
     mv = memoryview(v)  # We expose the buffer interface
-    if pytest.PY3:
+    if not pytest.PY2:
         assert mv[2] == 5
         mv[2] = 6
     else: