Add tests for saferepr

Author: Anusha Shekhar

testing/test_tracer.py

@@ -2,6 +2,7 @@
 
 import pytest
 
+from pluggy._tracing import saferepr, DEFAULT_REPR_MAX_SIZE
 from pluggy._tracing import TagTracer
 
 
@@ -77,3 +78,173 @@ def test_setprocessor(rootlogger: TagTracer) -> None:
     log2("seen")
     tags, args = l2[0]
     assert args == ("seen",)
+
+def test_saferepr_simple_repr():
+    assert saferepr(1) == "1"
+    assert saferepr(None) == "None"
+
+
+def test_saferepr_maxsize():
+    s = saferepr("x" * 50, maxsize=25)
+    assert len(s) == 25
+    expected = repr("x" * 10 + "..." + "x" * 10)
+    assert s == expected
+
+
+def test_saferepr_no_maxsize():
+    text = "x" * DEFAULT_REPR_MAX_SIZE * 10
+    s = saferepr(text, maxsize=None)
+    expected = repr(text)
+    assert s == expected
+
+
+def test_saferepr_maxsize_error_on_instance():
+    class A:
+        def __repr__(self):
+            raise ValueError("...")
+
+    s = saferepr(("*" * 50, A()), maxsize=25)
+    assert len(s) == 25
+    assert s[0] == "(" and s[-1] == ")"
+
+
+def test_saferepr_exceptions() -> None:
+    class BrokenRepr:
+        def __init__(self, ex):
+            self.ex = ex
+
+        def __repr__(self):
+            raise self.ex
+
+    class BrokenReprException(Exception):
+        __str__ = None  # type: ignore[assignment]
+        __repr__ = None  # type: ignore[assignment]
+
+    assert "Exception" in saferepr(BrokenRepr(Exception("broken")))
+    s = saferepr(BrokenReprException("really broken"))
+    assert "TypeError" in s
+    assert "TypeError" in saferepr(BrokenRepr("string"))
+
+    none = None
+    try:
+        none()  # type: ignore[misc]
+    except BaseException as exc:
+        exp_exc = repr(exc)
+    obj = BrokenRepr(BrokenReprException("omg even worse"))
+    s2 = saferepr(obj)
+    assert s2 == (
+        "<[unpresentable exception ({!s}) raised in repr()] BrokenRepr object at 0x{:x}>".format(
+            exp_exc, id(obj)
+        )
+    )
+
+
+def test_saferepr_baseexception():
+    """Test saferepr() with BaseExceptions, which includes pytest outcomes."""
+
+    class RaisingOnStrRepr(BaseException):
+        def __init__(self, exc_types):
+            self.exc_types = exc_types
+
+        def raise_exc(self, *args):
+            try:
+                self.exc_type = self.exc_types.pop(0)
+            except IndexError:
+                pass
+            if hasattr(self.exc_type, "__call__"):
+                raise self.exc_type(*args)
+            raise self.exc_type
+
+        def __str__(self):
+            self.raise_exc("__str__")
+
+        def __repr__(self):
+            self.raise_exc("__repr__")
+
+    class BrokenObj:
+        def __init__(self, exc):
+            self.exc = exc
+
+        def __repr__(self):
+            raise self.exc
+
+        __str__ = __repr__
+
+    baseexc_str = BaseException("__str__")
+    obj = BrokenObj(RaisingOnStrRepr([BaseException]))
+    assert saferepr(obj) == (
+        "<[unpresentable exception ({!r}) "
+        "raised in repr()] BrokenObj object at 0x{:x}>".format(baseexc_str, id(obj))
+    )
+    obj = BrokenObj(RaisingOnStrRepr([RaisingOnStrRepr([BaseException])]))
+    assert saferepr(obj) == (
+        "<[{!r} raised in repr()] BrokenObj object at 0x{:x}>".format(
+            baseexc_str, id(obj)
+        )
+    )
+
+    with pytest.raises(KeyboardInterrupt):
+        saferepr(BrokenObj(KeyboardInterrupt()))
+
+    with pytest.raises(SystemExit):
+        saferepr(BrokenObj(SystemExit()))
+
+    with pytest.raises(KeyboardInterrupt):
+        saferepr(BrokenObj(RaisingOnStrRepr([KeyboardInterrupt])))
+
+    with pytest.raises(SystemExit):
+        saferepr(BrokenObj(RaisingOnStrRepr([SystemExit])))
+
+    with pytest.raises(KeyboardInterrupt):
+        print(saferepr(BrokenObj(RaisingOnStrRepr([BaseException, KeyboardInterrupt]))))
+
+    with pytest.raises(SystemExit):
+        saferepr(BrokenObj(RaisingOnStrRepr([BaseException, SystemExit])))
+
+
+def test_saferepr_buggy_builtin_repr():
+    # Simulate a case where a repr for a builtin raises.
+    # reprlib dispatches by type name, so use "int".
+
+    class int:
+        def __repr__(self):
+            raise ValueError("Buggy repr!")
+
+    assert "Buggy" in saferepr(int())
+
+
+def test_saferepr_big_repr():
+    from _pytest._io.saferepr import SafeRepr
+
+    assert len(saferepr(range(1000))) <= len("[" + SafeRepr(0).maxlist * "1000" + "]")
+
+
+def test_saferepr_repr_on_newstyle() -> None:
+    class Function:
+        def __repr__(self):
+            return "<%s>" % (self.name)  # type: ignore[attr-defined]
+
+    assert saferepr(Function())
+
+
+def test_saferepr_unicode():
+    val = "£€"
+    reprval = "'£€'"
+    assert saferepr(val) == reprval
+
+
+def test_saferepr_broken_getattribute():
+    """saferepr() can create proper representations of classes with
+    broken __getattribute__ (#7145)
+    """
+
+    class SomeClass:
+        def __getattribute__(self, attr):
+            raise RuntimeError
+
+        def __repr__(self):
+            raise RuntimeError
+
+    assert saferepr(SomeClass()).startswith(
+        "<[RuntimeError() raised in repr()] SomeClass object at 0x"
+    )