diff --git a/boltons/queueutils.py b/boltons/queueutils.py
index 59d478a..e061e16 100644
--- a/boltons/queueutils.py
+++ b/boltons/queueutils.py
@@ -68,12 +68,12 @@ class BasePriorityQueue(object):
 
     Args:
         priority_key (callable): A function that takes *priority* as
-            passed in by :meth:`add` and returns an integer
+            passed in by :meth:`add` and returns a real number
             representing the effective priority.
 
     """
     # negating priority means larger numbers = higher priority
-    _default_priority_key = staticmethod(lambda p: -int(p or 0))
+    _default_priority_key = staticmethod(lambda p: -float(p or 0))
     _backend_type = list
 
     def __init__(self, **kw):

Priority queue does not support float priorities
Through a lot of painful debugging in a larger codebase, I found that both of boltons priority queue implementations treat a float priority `p` as if it were `int(p)`.

```
In [1]: from boltons.queueutils import PriorityQueue

In [2]: items = [('a', 0.8), ('b', 0.9), ('c', 0.6), ('d', 1.8), ('e', 1.9), ('f', 1.6)]

In [3]: q = PriorityQueue()

In [4]: for i, p in items: q.add(i, p)

In [5]: for i in range(6): print(q.pop())
d
e
f
a
b
c
```

See the behavior that personally I would expect in this situation, exhibited by a depq package for double-ended priority queues:
```
In [6]: from depq import DEPQ

In [7]: q = DEPQ(items)

In [8]: for i in range(6): print(q.popfirst())
('e', 1.9)
('d', 1.8)
('f', 1.6)
('b', 0.9)
('a', 0.8)
('c', 0.6)
```

I believe the current behavior should be explicitly documented. It's not clear that the priorities would be treated as if they were floored neither from the current docs nor from a brief look at the source.
diff --git a/tests/test_queueutils.py b/tests/test_queueutils.py
index 8d83671..710a0cd 100644
--- a/tests/test_queueutils.py
+++ b/tests/test_queueutils.py
@@ -5,14 +5,36 @@ from boltons.queueutils import SortedPriorityQueue, HeapPriorityQueue
 
 def _test_priority_queue(queue_type):
     pq = queue_type()
-    func = lambda x: x
-    pq.add(func)
-    pq.remove(func)
-    pq.add(func)
-    pq.add(func)
+    item1 = 'a'
+    item2 = 'b'
+    item3 = 'c'
+    pq.add(item1)
+    pq.remove(item1)
+
+    # integer priorities
+    pq.add(item1, 2)
+    pq.add(item2, 9)
+    pq.add(item3, 7)
+    assert len(pq) == 3
+    assert item2 == pq.pop()
+    assert len(pq) == 2
+    assert item3 == pq.pop()
     assert len(pq) == 1
-    assert func == pq.pop()
+    assert item1 == pq.pop()
     assert len(pq) == 0
+
+    # float priorities
+    pq.add(item1, 0.2)
+    pq.add(item2, 0.9)
+    pq.add(item3, 0.7)
+    assert len(pq) == 3
+    assert item2 == pq.pop()
+    assert len(pq) == 2
+    assert item3 == pq.pop()
+    assert len(pq) == 1
+    assert item1 == pq.pop()
+    assert len(pq) == 0
+
     try:
         pq.pop()
     except IndexError:

pip install -e .[dev]
parse_log_pytest
requirements.txt
pytest pytest-cov pytest-xdist pytest-mock pytest-asyncio
3.7
requirements-test.txt
pytest --no-header -rA --tb=line --color=no -p no:cacheprovider -W ignore::DeprecationWarning
-e git+https://github.com/mahmoud/boltons.git@a065dc576c1dc01e9539d973dfb961591ecee427#egg=boltons
certifi @ file:///croot/certifi_1671487769961/work/certifi
coverage==4.5.1
exceptiongroup==1.2.2
execnet==2.0.2
importlib-metadata==6.7.0
iniconfig==2.0.0
packaging==24.0
pluggy==0.13.1
py==1.5.4
pytest==7.4.4
pytest-asyncio==0.21.2
pytest-cov==2.5.1
pytest-mock==3.11.1
pytest-xdist==3.5.0
six==1.17.0
tomli==2.0.1
tox==2.9.1
tox-virtualenv-no-download==1.0.2
typing_extensions==4.7.1
virtualenv==15.0.2
zipp==3.15.0

name: boltons
channels:
  - defaults
  - https://repo.anaconda.com/pkgs/main
  - https://repo.anaconda.com/pkgs/r
  - conda-forge
dependencies:
  - _libgcc_mutex=0.1=main
  - _openmp_mutex=5.1=1_gnu
  - ca-certificates=2025.2.25=h06a4308_0
  - certifi=2022.12.7=py37h06a4308_0
  - ld_impl_linux-64=2.40=h12ee557_0
  - libffi=3.4.4=h6a678d5_1
  - libgcc-ng=11.2.0=h1234567_1
  - libgomp=11.2.0=h1234567_1
  - libstdcxx-ng=11.2.0=h1234567_1
  - ncurses=6.4=h6a678d5_0
  - openssl=1.1.1w=h7f8727e_0
  - pip=22.3.1=py37h06a4308_0
  - python=3.7.16=h7a1cb2a_0
  - readline=8.2=h5eee18b_0
  - setuptools=65.6.3=py37h06a4308_0
  - sqlite=3.45.3=h5eee18b_0
  - tk=8.6.14=h39e8969_0
  - wheel=0.38.4=py37h06a4308_0
  - xz=5.6.4=h5eee18b_1
  - zlib=1.2.13=h5eee18b_1
  - pip:
      - coverage==4.5.1
      - exceptiongroup==1.2.2
      - execnet==2.0.2
      - importlib-metadata==6.7.0
      - iniconfig==2.0.0
      - packaging==24.0
      - pluggy==0.13.1
      - py==1.5.4
      - pytest==7.4.4
      - pytest-asyncio==0.21.2
      - pytest-cov==2.5.1
      - pytest-mock==3.11.1
      - pytest-xdist==3.5.0
      - six==1.17.0
      - tomli==2.0.1
      - tox==2.9.1
      - tox-virtualenv-no-download==1.0.2
      - typing-extensions==4.7.1
      - virtualenv==15.0.2
      - zipp==3.15.0
prefix: /opt/conda/envs/boltons

tests/test_queueutils.py::test_heap_queue tests/test_queueutils.py::test_sorted_queue
boltons/queueutils.py
boltons/queueutils.py