fix: correct class name in Long{AboveMax,BelowMin} type-change error

LongAboveMax.to() and LongBelowMin.to() raised a TypeError whose message
named IntAboveMax/IntBelowMin, a copy-paste leftover from the Int singletons
above them. When a long overflow literal is asked to convert to an unsupported
type, the diagnostic misidentified it as an int literal, which is misleading
when debugging.

Point each message at its own class and add regression tests covering both the
successful conversion and the corrected error message for the long singletons.

Author: anxkhn

pyiceberg/expressions/literals.py

@@ -251,7 +251,7 @@ def __init__(self) -> None:
 
     @singledispatchmethod
     def to(self, type_var: IcebergType) -> Literal:  # type: ignore
-        raise TypeError("Cannot change the type of IntAboveMax")
+        raise TypeError("Cannot change the type of LongAboveMax")
 
     @to.register(LongType)
     def _(self, _: LongType) -> Literal[int]:
@@ -264,7 +264,7 @@ def __init__(self) -> None:
 
     @singledispatchmethod
     def to(self, type_var: IcebergType) -> Literal:  # type: ignore
-        raise TypeError("Cannot change the type of IntBelowMin")
+        raise TypeError("Cannot change the type of LongBelowMin")
 
     @to.register(LongType)
     def _(self, _: LongType) -> Literal[int]:

tests/expressions/test_literals.py

@@ -633,6 +633,34 @@ def test_below_min_int() -> None:
     assert b.to(IntegerType()) == IntBelowMin()
 
 
+def test_above_max_long() -> None:
+    a = LongAboveMax()
+    # singleton
+    assert a == LongAboveMax()
+    assert str(a) == "LongAboveMax"
+    assert repr(a) == "LongAboveMax()"
+    assert a.value == LongType.max
+    assert a == eval(repr(a))
+    assert a.to(LongType()) == LongAboveMax()
+    with pytest.raises(TypeError) as e:
+        a.to(IntegerType())
+    assert "Cannot change the type of LongAboveMax" in str(e.value)
+
+
+def test_below_min_long() -> None:
+    b = LongBelowMin()
+    # singleton
+    assert b == LongBelowMin()
+    assert str(b) == "LongBelowMin"
+    assert repr(b) == "LongBelowMin()"
+    assert b == eval(repr(b))
+    assert b.value == LongType.min
+    assert b.to(LongType()) == LongBelowMin()
+    with pytest.raises(TypeError) as e:
+        b.to(IntegerType())
+    assert "Cannot change the type of LongBelowMin" in str(e.value)
+
+
 def test_invalid_boolean_conversions() -> None:
     assert_invalid_conversions(
         literal(True),