diff --git a/lint_requirements.txt b/lint_requirements.txt
index f7e27d6..1246a40 100644
--- a/lint_requirements.txt
+++ b/lint_requirements.txt
@@ -1,5 +1,5 @@
 # Lint requirements
-ruff~=0.15.0
+ruff~=0.15.1
 mypy~=1.19.1
 shellcheck-py~=0.11.0.1
 
diff --git a/tests/scripts/config.source b/tests/scripts/config.source
index 5901cc6..cfa0a62 100644
--- a/tests/scripts/config.source
+++ b/tests/scripts/config.source
@@ -80,4 +80,28 @@ expect_deny () {
   fi
 }
 
+# Expects the provided test to pass
+# Supresses all output, which is redirected to ASSERTION_OUTPUT and
+# ASSERTION_ERROUTPUT so as not to overwrite the latest OUTPUT and ERROUTPUT.
+# That way we can test several assertions in a row.
+# Reports verbosely on failure.
+assert () {
+  if {
+    [[ "$@" ]]
+  } 1>log.out 2>log.err
+  then
+    echo "SUCCESS [$@]" >&3
+    ASSERTION_OUTPUT="$(cat log.out)"
+    ASSERTION_ERROUTPUT="$(cat log.err)"
+  else
+    echo "FAILURE [$@]" >&3
+    echo "=== STDOUT ===" >&3
+    cat log.out >&3
+    echo "=== STDERR ===" >&3
+    cat log.err >&3
+    echo "==============" >&3
+    false
+  fi
+}
+
 set -eu