diff --git a/test/system/505-networking-pasta.bats b/test/system/505-networking-pasta.bats
index af342ddc84..944ea6b4e3 100644
--- a/test/system/505-networking-pasta.bats
+++ b/test/system/505-networking-pasta.bats
@@ -254,10 +254,6 @@ function pasta_test_do() {
     assert "${output}" = "${expect}" "Mismatch between data sent and received"
 }
 
-function teardown() {
-    rm -f "${XFER_FILE}"
-}
-
 ### Addresses ##################################################################
 
 @test "IPv4 default address assignment" {
diff --git a/test/system/helpers.bash b/test/system/helpers.bash
index d69b717205..ded6de6425 100644
--- a/test/system/helpers.bash
+++ b/test/system/helpers.bash
@@ -210,10 +210,20 @@ function basic_setup() {
     immediate-assertion-failures
 }
 
+# bail-now is how we terminate a test upon assertion failure.
+# By default, and the vast majority of the time, it just triggers
+# immediate test termination; but see defer-assertion-failures, below.
+function bail-now() {
+    # "false" does not apply to "bail now"! It means "nonzero exit",
+    # which BATS interprets as "yes, bail immediately".
+    false
+}
+
+# Invoked on teardown: will terminate immediately if there have been
+# any deferred test failures; otherwise will reset back to immediate
+# test termination on future assertions.
 function immediate-assertion-failures() {
     function bail-now() {
-        # "false" does not apply to "bail now"! It means "nonzero exit",
-        # which BATS interprets as "yes, bail immediately".
         false
     }
 
@@ -225,6 +235,9 @@ function immediate-assertion-failures() {
     fi
 }
 
+# Used in special test circumstances--typically multi-condition loops--to
+# continue going even on assertion failures. The test will fail afterward,
+# usually in teardown. This can be useful to show failure patterns.
 function defer-assertion-failures() {
     function bail-now() {
         ASSERTION_FAILURES+="!"