diff --git a/server/BandwidthControllerTest.cpp b/server/BandwidthControllerTest.cpp
index 2b2ce6e..959ad9a 100644
--- a/server/BandwidthControllerTest.cpp
+++ b/server/BandwidthControllerTest.cpp
@@ -41,23 +41,15 @@
     }
     BandwidthController mBw;
 
-    void addPopenContents(std::string contents) {
-        sPopenContents.push_back(contents);
-    }
-
-    void addPopenContents(std::string contents1, std::string contents2) {
-        sPopenContents.push_back(contents1);
-        sPopenContents.push_back(contents2);
-    }
-
-    void clearPopenContents() {
-        sPopenContents.clear();
-    }
-
     void addIptablesRestoreOutput(std::string contents) {
         sIptablesRestoreOutput.push_back(contents);
     }
 
+    void addIptablesRestoreOutput(std::string contents1, std::string contents2) {
+        sIptablesRestoreOutput.push_back(contents1);
+        sIptablesRestoreOutput.push_back(contents2);
+    }
+
     void clearIptablesRestoreOutput() {
         sIptablesRestoreOutput.clear();
     }
@@ -229,17 +221,17 @@
     BandwidthController::TetherStats filter;
 
     // If no filter is specified, both IPv4 and IPv6 counters must have at least one interface pair.
-    addPopenContents(kIPv4TetherCounters, "");
+    addIptablesRestoreOutput(kIPv4TetherCounters);
     ASSERT_EQ(-1, mBw.getTetherStats(&cli, filter, err));
     expectNoSocketClientResponse(socketPair[1]);
-    clearPopenContents();
+    clearIptablesRestoreOutput();
 
-    addPopenContents("", kIPv6TetherCounters);
+    addIptablesRestoreOutput(kIPv6TetherCounters);
     ASSERT_EQ(-1, mBw.getTetherStats(&cli, filter, err));
-    clearPopenContents();
+    clearIptablesRestoreOutput();
 
     // IPv4 and IPv6 counters are properly added together.
-    addPopenContents(kIPv4TetherCounters, kIPv6TetherCounters);
+    addIptablesRestoreOutput(kIPv4TetherCounters, kIPv6TetherCounters);
     filter = BandwidthController::TetherStats();
     std::string expected =
             "114 wlan0 rmnet0 10002373 10026 20002002 20027\n"
@@ -248,83 +240,89 @@
     ASSERT_EQ(0, mBw.getTetherStats(&cli, filter, err));
     ASSERT_EQ(expected, readSocketClientResponse(socketPair[1]));
     expectNoSocketClientResponse(socketPair[1]);
-    clearPopenContents();
+    clearIptablesRestoreOutput();
 
     // Test filtering.
-    addPopenContents(kIPv4TetherCounters, kIPv6TetherCounters);
+    addIptablesRestoreOutput(kIPv4TetherCounters, kIPv6TetherCounters);
     filter = BandwidthController::TetherStats("bt-pan", "rmnet0", -1, -1, -1, -1);
     expected = "221 bt-pan rmnet0 107471 1040 1708806 1450\n";
     ASSERT_EQ(0, mBw.getTetherStats(&cli, filter, err));
     ASSERT_EQ(expected, readSocketClientResponse(socketPair[1]));
     expectNoSocketClientResponse(socketPair[1]);
-    clearPopenContents();
+    clearIptablesRestoreOutput();
 
-    addPopenContents(kIPv4TetherCounters, kIPv6TetherCounters);
+    addIptablesRestoreOutput(kIPv4TetherCounters, kIPv6TetherCounters);
     filter = BandwidthController::TetherStats("wlan0", "rmnet0", -1, -1, -1, -1);
     expected = "221 wlan0 rmnet0 10002373 10026 20002002 20027\n";
     ASSERT_EQ(0, mBw.getTetherStats(&cli, filter, err));
     ASSERT_EQ(expected, readSocketClientResponse(socketPair[1]));
-    clearPopenContents();
+    clearIptablesRestoreOutput();
 
     // Select nonexistent interfaces.
-    addPopenContents(kIPv4TetherCounters, kIPv6TetherCounters);
+    addIptablesRestoreOutput(kIPv4TetherCounters, kIPv6TetherCounters);
     filter = BandwidthController::TetherStats("rmnet0", "foo0", -1, -1, -1, -1);
     expected = "200 Tethering stats list completed\n";
     ASSERT_EQ(0, mBw.getTetherStats(&cli, filter, err));
     ASSERT_EQ(expected, readSocketClientResponse(socketPair[1]));
-    clearPopenContents();
+    clearIptablesRestoreOutput();
 
     // No stats with a filter: no error.
-    addPopenContents("", "");
+    addIptablesRestoreOutput("", "");
     ASSERT_EQ(0, mBw.getTetherStats(&cli, filter, err));
     ASSERT_EQ("200 Tethering stats list completed\n", readSocketClientResponse(socketPair[1]));
-    clearPopenContents();
+    clearIptablesRestoreOutput();
 
-    addPopenContents("foo", "foo");
+    addIptablesRestoreOutput("foo", "foo");
     ASSERT_EQ(0, mBw.getTetherStats(&cli, filter, err));
     ASSERT_EQ("200 Tethering stats list completed\n", readSocketClientResponse(socketPair[1]));
-    clearPopenContents();
+    clearIptablesRestoreOutput();
 
     // No stats and empty filter: error.
     filter = BandwidthController::TetherStats();
-    addPopenContents("", kIPv6TetherCounters);
+    addIptablesRestoreOutput("", kIPv6TetherCounters);
     ASSERT_EQ(-1, mBw.getTetherStats(&cli, filter, err));
     expectNoSocketClientResponse(socketPair[1]);
-    clearPopenContents();
+    clearIptablesRestoreOutput();
 
-    addPopenContents(kIPv4TetherCounters, "");
+    addIptablesRestoreOutput(kIPv4TetherCounters, "");
     ASSERT_EQ(-1, mBw.getTetherStats(&cli, filter, err));
     expectNoSocketClientResponse(socketPair[1]);
-    clearPopenContents();
+    clearIptablesRestoreOutput();
 
     // Include only one pair of interfaces and things are fine.
     std::vector<std::string> counterLines = android::base::Split(kIPv4TetherCounters, "\n");
     std::vector<std::string> brokenCounterLines = counterLines;
     counterLines.resize(4);
     std::string counters = android::base::Join(counterLines, "\n") + "\n";
-    addPopenContents(counters, counters);
+    addIptablesRestoreOutput(counters, counters);
     expected =
             "114 wlan0 rmnet0 4746 52 4004 54\n"
             "200 Tethering stats list completed\n";
     ASSERT_EQ(0, mBw.getTetherStats(&cli, filter, err));
     ASSERT_EQ(expected, readSocketClientResponse(socketPair[1]));
-    clearPopenContents();
+    clearIptablesRestoreOutput();
 
     // But if interfaces aren't paired, it's always an error.
+    err = "";
     counterLines.resize(3);
     counters = android::base::Join(counterLines, "\n") + "\n";
-    addPopenContents(counters, counters);
+    addIptablesRestoreOutput(counters, counters);
     ASSERT_EQ(-1, mBw.getTetherStats(&cli, filter, err));
     expectNoSocketClientResponse(socketPair[1]);
-    clearPopenContents();
+    clearIptablesRestoreOutput();
+
+    // Token unit test of the fact that we return the stats in the error message which the caller
+    // ignores.
+    std::string expectedError = counters;
+    EXPECT_EQ(expectedError, err);
 
     // popen() failing is always an error.
-    addPopenContents(kIPv4TetherCounters);
+    addIptablesRestoreOutput(kIPv4TetherCounters);
     ASSERT_EQ(-1, mBw.getTetherStats(&cli, filter, err));
     expectNoSocketClientResponse(socketPair[1]);
-    clearPopenContents();
-    addPopenContents(kIPv6TetherCounters);
+    clearIptablesRestoreOutput();
+    addIptablesRestoreOutput(kIPv6TetherCounters);
     ASSERT_EQ(-1, mBw.getTetherStats(&cli, filter, err));
     expectNoSocketClientResponse(socketPair[1]);
-    clearPopenContents();
+    clearIptablesRestoreOutput();
 }