diff --git a/src/pushsource/_impl/list_cmd.py b/src/pushsource/_impl/list_cmd.py
index 57f8fd4a..f9578a3d 100755
--- a/src/pushsource/_impl/list_cmd.py
+++ b/src/pushsource/_impl/list_cmd.py
@@ -25,15 +25,42 @@
 from argparse import ArgumentParser, RawDescriptionHelpFormatter
 import subprocess
 import sys
+import enum
 
 import attr
 import yaml
+from frozendict.core import frozendict
 
+import pushsource
 from pushsource import Source
 
 LOG = logging.getLogger("pushsource-ls")
 
 
+class ItemDumper(yaml.SafeDumper):
+    # Custom dumper adding support for any types appearing on pushitems
+    # which are not natively supported by pyyaml.
+
+    @classmethod
+    def represent_enum(cls, dumper: yaml.Dumper, value: enum.Enum):
+        # enums are unwrapped and represented using whatever's the underlying
+        # type, e.g. a string enum of value "foo" will be serialized the
+        # same as a plain string "foo".
+        return dumper.represent_data(value.value)
+
+    @classmethod
+    def add_enum_representers(cls):
+        # Register our enum representer for any enum classes in the API.
+        for attrname in dir(pushsource):
+            attrval = getattr(pushsource, attrname)
+            if isinstance(attrval, enum.EnumMeta):
+                cls.add_representer(attrval, cls.represent_enum)
+
+
+ItemDumper.add_enum_representers()
+ItemDumper.add_representer(frozendict, ItemDumper.represent_dict)
+
+
 def format_python(item):
     return repr(item) + ","
 
@@ -51,7 +78,7 @@ def format_python_black(item):
 
 def format_yaml(item):
     data = {type(item).__name__: attr.asdict(item, recurse=True)}
-    return yaml.dump([data], Dumper=yaml.SafeDumper)
+    return yaml.dump([data], Dumper=ItemDumper)
 
 
 def default_format():
diff --git a/src/pushsource/_impl/model/vms.py b/src/pushsource/_impl/model/vms.py
index 8d969f16..babc223a 100644
--- a/src/pushsource/_impl/model/vms.py
+++ b/src/pushsource/_impl/model/vms.py
@@ -19,6 +19,10 @@ class BootMode(enum.Enum):
     legacy = "legacy"
     """Supports only BIOS mode."""
 
+    def __repr__(self):
+        cls_name = self.__class__.__name__
+        return f"{cls_name}.{self.name}"
+
 
 @attr.s()
 class VMIRelease(object):
diff --git a/test-requirements.in b/test-requirements.in
index 18d404c8..62c7aa71 100644
--- a/test-requirements.in
+++ b/test-requirements.in
@@ -8,6 +8,7 @@ koji>=1.18
 mock
 more-executors
 pre-commit
+black
 pushcollector
 pylint
 pytest
diff --git a/test-requirements.txt b/test-requirements.txt
index aafd94e4..a0494be5 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -32,6 +32,30 @@ bandit==1.7.10 \
     --hash=sha256:59ed5caf5d92b6ada4bf65bc6437feea4a9da1093384445fed4d472acc6cff7b \
     --hash=sha256:665721d7bebbb4485a339c55161ac0eedde27d51e638000d91c8c2d68343ad02
     # via -r test-requirements.in
+black==24.10.0 \
+    --hash=sha256:14b3502784f09ce2443830e3133dacf2c0110d45191ed470ecb04d0f5f6fcb0f \
+    --hash=sha256:17374989640fbca88b6a448129cd1745c5eb8d9547b464f281b251dd00155ccd \
+    --hash=sha256:1c536fcf674217e87b8cc3657b81809d3c085d7bf3ef262ead700da345bfa6ea \
+    --hash=sha256:1cbacacb19e922a1d75ef2b6ccaefcd6e93a2c05ede32f06a21386a04cedb981 \
+    --hash=sha256:1f93102e0c5bb3907451063e08b9876dbeac810e7da5a8bfb7aeb5a9ef89066b \
+    --hash=sha256:2cd9c95431d94adc56600710f8813ee27eea544dd118d45896bb734e9d7a0dc7 \
+    --hash=sha256:30d2c30dc5139211dda799758559d1b049f7f14c580c409d6ad925b74a4208a8 \
+    --hash=sha256:394d4ddc64782e51153eadcaaca95144ac4c35e27ef9b0a42e121ae7e57a9175 \
+    --hash=sha256:3bb2b7a1f7b685f85b11fed1ef10f8a9148bceb49853e47a294a3dd963c1dd7d \
+    --hash=sha256:4007b1393d902b48b36958a216c20c4482f601569d19ed1df294a496eb366392 \
+    --hash=sha256:5a2221696a8224e335c28816a9d331a6c2ae15a2ee34ec857dcf3e45dbfa99ad \
+    --hash=sha256:63f626344343083322233f175aaf372d326de8436f5928c042639a4afbbf1d3f \
+    --hash=sha256:649fff99a20bd06c6f727d2a27f401331dc0cc861fb69cde910fe95b01b5928f \
+    --hash=sha256:680359d932801c76d2e9c9068d05c6b107f2584b2a5b88831c83962eb9984c1b \
+    --hash=sha256:846ea64c97afe3bc677b761787993be4991810ecc7a4a937816dd6bddedc4875 \
+    --hash=sha256:b5e39e0fae001df40f95bd8cc36b9165c5e2ea88900167bddf258bacef9bbdc3 \
+    --hash=sha256:ccfa1d0cb6200857f1923b602f978386a3a2758a65b52e0950299ea014be6800 \
+    --hash=sha256:d37d422772111794b26757c5b55a3eade028aa3fde43121ab7b673d050949d65 \
+    --hash=sha256:ddacb691cdcdf77b96f549cf9591701d8db36b2f19519373d60d31746068dbf2 \
+    --hash=sha256:e6668650ea4b685440857138e5fe40cde4d652633b1bdffc62933d0db4ed9812 \
+    --hash=sha256:f9da3333530dbcecc1be13e69c250ed8dfa67f43c4005fb537bb426e19200d50 \
+    --hash=sha256:fe4d6476887de70546212c99ac9bd803d90b42fc4767f058a0baa895013fbb3e
+    # via -r test-requirements.in
 certifi==2024.8.30 \
     --hash=sha256:922820b53db7a7257ffbda3f597266d435245903d80737e34f8a45ff3e3230d8 \
     --hash=sha256:bec941d2aa8195e248a60b31ff9f0558284cf01a52591ceda73ea9afffd69fd9
@@ -218,6 +242,10 @@ charset-normalizer==3.4.0 \
     --hash=sha256:fe9f97feb71aa9896b81973a7bbada8c49501dc73e58a10fcef6663af95e5079 \
     --hash=sha256:ffc519621dce0c767e96b9c53f09c5d215578e10b02c285809f76509a3931482
     # via requests
+click==8.1.7 \
+    --hash=sha256:ae74fb96c20a0277a1d615f1e4d73c8414f5a98db8b799a7931d1582f3390c28 \
+    --hash=sha256:ca9853ad459e787e2192211578cc907e7594e294c7ccc834310722b41b9ca6de
+    # via black
 coverage[toml]==7.6.4 \
     --hash=sha256:00a1d69c112ff5149cabe60d2e2ee948752c975d95f1e1096742e6077affd376 \
     --hash=sha256:023bf8ee3ec6d35af9c1c6ccc1d18fa69afa1cb29eaac57cb064dbb262a517f9 \
@@ -565,6 +593,10 @@ more-executors==2.11.4 \
     #   -r requirements.in
     #   -r test-requirements.in
     #   pushcollector
+mypy-extensions==1.0.0 \
+    --hash=sha256:4392f6c0eb8a5668a69e23d168ffa70f0be9ccfd32b5cc2d26a34ae5b844552d \
+    --hash=sha256:75dbf8955dc00442a438fc4d0666508a9a97b6bd41aa2f0ffe9d2f2725af0782
+    # via black
 nodeenv==1.9.1 \
     --hash=sha256:6ec12890a2dab7946721edbfbcd91f3319c6ccc9aec47be7c7e6b7011ee6645f \
     --hash=sha256:ba11c9782d29c27c70ffbdda2d7415098754709be8a7056d79a737cd901155c9
@@ -573,8 +605,13 @@ packaging==24.1 \
     --hash=sha256:026ed72c8ed3fcce5bf8950572258698927fd1dbda10a5e981cdf0ac37f4f002 \
     --hash=sha256:5b8f2217dbdbd2f7f384c41c628544e6d52f2d0f53c6d0c3ea61aa5d1d7ff124
     # via
+    #   black
     #   pytest
     #   sphinx
+pathspec==0.12.1 \
+    --hash=sha256:a0d503e138a4c123b27490a4f7beda6a01c6f288df0e4a8b79c7eb0dc7b4cc08 \
+    --hash=sha256:a482d51503a1ab33b1c67a6c3813a26953dbdc71c31dacaef9a838c4e29f5712
+    # via black
 pbr==6.1.0 \
     --hash=sha256:788183e382e3d1d7707db08978239965e8b9e4e5ed42669bf4758186734d5f24 \
     --hash=sha256:a776ae228892d8013649c0aeccbb3d5f99ee15e005a4cbb7e61d55a067b28a2a
@@ -587,6 +624,7 @@ platformdirs==4.3.6 \
     --hash=sha256:357fb2acbc885b0419afd3ce3ed34564c13c9b95c89360cd9563f73aa5e2b907 \
     --hash=sha256:73e575e1408ab8103900836b97580d5307456908a03e92031bab39e4554cc3fb
     # via
+    #   black
     #   pylint
     #   virtualenv
 pluggy==1.5.0 \
@@ -899,6 +937,7 @@ tomli==2.0.2 \
     --hash=sha256:2ebe24485c53d303f690b0ec092806a085f07af5a5aa1464f3931eec36caaa38 \
     --hash=sha256:d46d457a85337051c36524bc5349dd91b1877838e2979ac5ced3e710ed8a60ed
     # via
+    #   black
     #   coverage
     #   pylint
     #   pytest
diff --git a/tests/cmd/test_list_cmd.py b/tests/cmd/test_list_cmd.py
index 5138b9e6..591d923c 100644
--- a/tests/cmd/test_list_cmd.py
+++ b/tests/cmd/test_list_cmd.py
@@ -2,6 +2,7 @@
 import sys
 import logging
 import textwrap
+import itertools
 
 import yaml
 import pytest
@@ -69,6 +70,35 @@ def test_typical(monkeypatch, capsys):
     assert "My wonderful ISO" in out
 
 
+@pytest.mark.parametrize(
+    "format,case",
+    itertools.product(
+        # The supported formats
+        ["yaml", "python", "python-black"],
+        # The staging areas.
+        # Note: limited to 'simple' because there are some staging areas
+        # intentionally set up to trigger errors, which will also cause
+        # pushsource-ls to fail.
+        [
+            e.name
+            for e in os.scandir(STAGED_DATA_DIR)
+            if e.is_dir() and "simple" in e.name
+        ],
+    ),
+)
+def test_staged(monkeypatch, format, case):
+    """pushsource-ls runs without crashing with all formats on staging areas
+    in the test data.
+    """
+
+    monkeypatch.setattr(
+        sys, "argv", ["", "--format", format, f"staged:{STAGED_DATA_DIR}/{case}"]
+    )
+
+    # It should run OK
+    list_main()
+
+
 def test_valid_yaml(monkeypatch, capsys):
     """'--format yaml' generates valid YAML."""