Fix decimal.FloatOperation error in pytest.approx Decimal __repr__

src/_pytest/python_api.py

@@ -530,6 +530,17 @@ class ApproxDecimal(ApproxScalar):
     DEFAULT_ABSOLUTE_TOLERANCE = Decimal("1e-12")
     DEFAULT_RELATIVE_TOLERANCE = Decimal("1e-6")
 
+    def __repr__(self):
+        rel = Decimal(str(self.rel)) if isinstance(self.rel, float) else self.rel
+        abs_ = Decimal(str(self.abs)) if isinstance(self.abs, float) else self.abs
+        if rel is not None and Decimal("1e-3") <= rel <= Decimal("1e3"):
+            tol_str = f"{rel:.1e}"
+        elif abs_ is not None:
+            tol_str = f"{abs_:.1e}"
+        else:
+            tol_str = "???"
+        return f"{self.expected} ± {tol_str}"
+
 
 def approx(expected, rel=None, abs=None, nan_ok: bool = False) -> ApproxBase:
     """Assert that two numbers (or two ordered sequences of numbers) are equal to each other

testing/test_decimal_approx.py

@@ -0,0 +1,16 @@
+from __future__ import annotations
+
+import decimal
+
+import pytest
+
+
+def test_decimal_approx_repr_issue() -> None:
+    trap = decimal.getcontext().traps[decimal.FloatOperation]
+    decimal.getcontext().traps[decimal.FloatOperation] = False
+
+    approx_obj = pytest.approx(decimal.Decimal("2.60"))
+    print(f"Attempting to represent pytest.approx(Decimal): {approx_obj}")
+    assert decimal.Decimal("2.600001") == approx_obj
+
+    decimal.getcontext().traps[decimal.FloatOperation] = trap