diff --git a/flow/record/adapter/text.py b/flow/record/adapter/text.py
index 7df23792..91512a95 100644
--- a/flow/record/adapter/text.py
+++ b/flow/record/adapter/text.py
@@ -26,6 +26,16 @@
 
 
 class DefaultMissing(dict):
+    """A dictionary subclass that returns a formatted string for missing keys.
+
+    Example:
+        >>> d = DefaultMissing({"foo": "bar"})
+        >>> d['foo']
+        'bar'
+        >>> d['missing_key']
+        '{missing_key}'
+    """
+
     def __missing__(self, key: str) -> str:
         return key.join("{}")
 
diff --git a/tests/docs/Makefile b/tests/docs/Makefile
index 69e00981..e693b42d 100644
--- a/tests/docs/Makefile
+++ b/tests/docs/Makefile
@@ -3,7 +3,7 @@
 
 # You can set these variables from the command line, and also
 # from the environment for the first two.
-SPHINXOPTS    ?= -jauto
+SPHINXOPTS    ?= -jauto -w $(BUILDDIR)/warnings.log --fail-on-warning
 SPHINXBUILD   ?= sphinx-build
 SOURCEDIR     = .
 BUILDDIR      = build
diff --git a/tests/docs/conf.py b/tests/docs/conf.py
index 021c44e5..7a368176 100644
--- a/tests/docs/conf.py
+++ b/tests/docs/conf.py
@@ -32,3 +32,8 @@
 autodoc_member_order = "groupwise"
 
 autosectionlabel_prefix_document = True
+
+suppress_warnings = [
+    # https://github.com/readthedocs/sphinx-autoapi/issues/285
+    "autoapi.python_import_resolution",
+]