diff --git a/test/events.c b/test/events.c
index 940bcedc..dfda3b63 100644
--- a/test/events.c
+++ b/test/events.c
@@ -94,10 +94,10 @@ static void runFull(testingT *t, const char *file, long line, uiEvent *e, void *
 		if (h->gotRun && h->wantRun) {
 			// only check these if it was correctly run, to reduce noise if the above failed
 			if (h->gotSender != h->wantSender)
-				testingTErrorfFull(t, file, line, "incorrect sender seen by %s:" diffx("%p"),
+				testingTErrorfFull(t, file, line, "incorrect sender seen by %s:" diff("%p"),
 					h->name, h->gotSender, h->wantSender);
 			if (h->gotArgs != h->wantArgs)
-				testingTErrorfFull(t, file, line, "incorrect args seen by %s:" diffx("%p"),
+				testingTErrorfFull(t, file, line, "incorrect args seen by %s:" diff("%p"),
 					h->name, h->gotArgs, h->wantArgs);
 		}
 		if (h->validID) {
@@ -111,7 +111,7 @@ static void runFull(testingT *t, const char *file, long line, uiEvent *e, void *
 		h++;
 	}
 	if (gotRunCount != wantRunCount)
-		testingTErrorfFull(t, file, line, "incorrect number of handler runs:" diffx("%d"),
+		testingTErrorfFull(t, file, line, "incorrect number of handler runs:" diff("%d"),
 			gotRunCount, wantRunCount);
 }
 
diff --git a/test/initmain.c b/test/initmain.c
index 5db32a04..0266a9bd 100644
--- a/test/initmain.c
+++ b/test/initmain.c
@@ -24,7 +24,7 @@ testingTestInSet(beforeTests, Init)
 	if (uiInit(&err, &err))
 		testingTErrorf(t, "uiInit() with non-NULL options succeeded; expected failure");
 	if (strcmp(err.Message, errInvalidOptions) != 0)
-		testingTErrorf(t, "uiInit() with non-NULL options returned bad error message:" diffx("%s"),
+		testingTErrorf(t, "uiInit() with non-NULL options returned bad error message:" diff("%s"),
 			err.Message, errInvalidOptions);
 }
 
@@ -37,7 +37,7 @@ testingTest(InitAfterInitialized)
 	if (uiInit(NULL, &err))
 		testingTErrorf(t, "uiInit() after a previous successful call succeeded; expected failure");
 	if (strcmp(err.Message, errAlreadyInitialized) != 0)
-		testingTErrorf(t, "uiInit() after a previous successful call returned bad error message:" diffx("%s"),
+		testingTErrorf(t, "uiInit() after a previous successful call returned bad error message:" diff("%s"),
 			err.Message, errAlreadyInitialized);
 }
 
@@ -69,7 +69,7 @@ testingTest(QueueMain)
 	uiQueueMain(queued, &p);
 	timeout_uiMain(t, 5 * timerSecond);
 	if (p.flag != 1)
-		testingTErrorf(t, "uiQueueMain() didn't set flag properly:" diffx("%d"),
+		testingTErrorf(t, "uiQueueMain() didn't set flag properly:" diff("%d"),
 			p.flag, 1);
 }
 
@@ -117,12 +117,12 @@ static void checkOrderFull(testingT *t, const char *file, long line, uint32_t fl
 		return;
 	for (i = 1; i < 6; i++)
 		if (flag == orders[i].result) {
-			testingTErrorfFull(t, file, line, "wrong order:" diffx("%" PRIu32 " (%s)"),
+			testingTErrorfFull(t, file, line, "wrong order:" diff("%" PRIu32 " (%s)"),
 				flag, orders[i].order,
 				orders[0].result, orders[0].order);
 			return;
 		}
-	testingTErrorfFull(t, file, line, "wrong result:" diffx("%" PRIu32 " (%s)"),
+	testingTErrorfFull(t, file, line, "wrong result:" diff("%" PRIu32 " (%s)"),
 		flag, "unknown order",
 		orders[0].result, orders[0].order);
 }
@@ -165,7 +165,7 @@ testingTest(QueueMain_DifferentThread)
 	if (p.err != 0)
 		testingTErrorf(t, "error sleeping in thread to ensure a high likelihood the uiQueueMain() is run after uiMain() starts: " timerSysErrorFmt, timerSysErrorFmtArg(p.err));
 	if (p.flag != 1)
-		testingTErrorf(t, "uiQueueMain() didn't set flag properly:" diffx("%d"),
+		testingTErrorf(t, "uiQueueMain() didn't set flag properly:" diff("%d"),
 			p.flag, 1);
 }
 
diff --git a/test/main.c b/test/main.c
index 68b432c9..520180ff 100644
--- a/test/main.c
+++ b/test/main.c
@@ -16,7 +16,7 @@ void catchProgrammerError(const char *prefix, const char *msg, const char *suffi
 	if (internal)
 		testingTErrorfFull(errorParams.t, errorParams.file, errorParams.line, "%s error is marked internal; should not have been", errorParams.exprstr);
 	if (strstr(msg, errorParams.msgWant) == NULL)
-		testingTErrorf(errorParams.t, errorParams.file, errorParams.line, "%s: message doesn't contain expected substring:" diffx("%s"),
+		testingTErrorf(errorParams.t, errorParams.file, errorParams.line, "%s: message doesn't contain expected substring:" diff("%s"),
 			errorParams.exprstr, msg, errorParams.msgWant);
 }
 
diff --git a/test/noinitwrongthread.c b/test/noinitwrongthread.c
index 30d5d7df..99a52ab5 100644
--- a/test/noinitwrongthread.c
+++ b/test/noinitwrongthread.c
@@ -125,7 +125,7 @@ static void reportCases(testingT *t, struct errorCase *p)
 		if (p->internalGot)
 			testingTErrorfFull(t, p->file, p->line, "%s error is marked internal; should not have been", p->name);
 		if (p->msgGot != NULL)
-			testingTErrorfFull(t, p->file, p->line, "%s message doesn't contain expected substring:" diffx("%s"),
+			testingTErrorfFull(t, p->file, p->line, "%s message doesn't contain expected substring:" diff("%s"),
 				p->name, p->msgGot, p->msgWant);
 		p = p->next;
 	}
diff --git a/test/test.h b/test/test.h
index 9ba03cb1..99be337a 100644
--- a/test/test.h
+++ b/test/test.h
@@ -10,7 +10,7 @@
 #include "lib/thread.h"
 #include "lib/timer.h"
 
-#define diffx(fmt) "\ngot  " fmt "\nwant " fmt
+#define diff(fmt) "\ngot  " fmt "\nwant " fmt
 
 // main.c
 extern void timeoutMain(void *data);