diff --git a/test/errors.c b/test/errors.c
index fc6be3bb..790a4aca 100644
--- a/test/errors.c
+++ b/test/errors.c
@@ -4,10 +4,9 @@
 struct checkProgrammerErrorParams {
 	const char *file;
 	long line;
-	void (*f)(void *data);
-	void *data;
 	bool inThread;
 	bool caught;
+	void (*f)(void);
 	char *msgGot;
 	const char *msgWant;
 };
@@ -30,7 +29,7 @@ static void checkProgrammerErrorThreadProc(void *data)
 {
 	struct checkProgrammerErrorParams *p = (struct checkProgrammerErrorParams *) data;
 
-	(*(p->f))(p->data);
+	(*(p->f))();
 }
 
 static void checkProgrammerErrorSubtestImpl(testingT *t, void *data)
@@ -50,7 +49,7 @@ static void checkProgrammerErrorSubtestImpl(testingT *t, void *data)
 		if (err != 0)
 			testingTFatalfFull(t, p->file, p->line, "error waiting for thread to finish: " threadSysErrorFmt, threadSysErrorFmtArg(err));
 	} else
-		(*(p->f))(p->data);
+		(*(p->f))();
 	if (!p->caught)
 		testingTErrorfFull(t, p->file, p->line, "did not throw a programmer error; should have");
 	if (p->msgGot != NULL) {
@@ -60,16 +59,20 @@ static void checkProgrammerErrorSubtestImpl(testingT *t, void *data)
 	}
 }
 
-void checkProgrammerErrorFull(testingT *t, const char *file, long line, const char *name, void (*f)(void *data), void *data, const char *msgWant, bool inThread)
+void checkProgrammerErrorsFull(testingT *t, const char *file, long line, const struct checkErrorCase *cases, bool inThread)
 {
+	const struct checkErrorCase *c;
 	struct checkProgrammerErrorParams p;
 
 	memset(&p, 0, sizeof (struct checkProgrammerErrorParams));
 	p.file = file;
 	p.line = line;
-	p.f = f;
-	p.data = data;
 	p.inThread = inThread;
-	p.msgWant = msgWant;
-	testingTRun(t, name, checkProgrammerErrorSubtestImpl, &p);
+	for (c = cases; c->name != NULL; c++) {
+		p.caught = false;
+		p.f = c->f;
+		p.msgGot = NULL;
+		p.msgWant = c->msgWant;
+		testingTRun(t, c->name, checkProgrammerErrorSubtestImpl, &p);
+	}
 }
diff --git a/test/lib/testing.h b/test/lib/testing.h
index 2690f3ba..3639cd6f 100644
--- a/test/lib/testing.h
+++ b/test/lib/testing.h
@@ -4,6 +4,10 @@
 #include <stdbool.h>
 #include <stdint.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #define testingprivImplName(basename) testingprivImpl ## basename
 
 #define testingprivScaffoldName(basename) testingprivScaffold ## basename
@@ -104,3 +108,7 @@ extern void testingprivTLogvfFullThen(testingT *, void (*)(testingT *), const ch
 // Utility functions, provided here to avoid mucking up the sharedbits functions.
 extern char *testingUtilStrdup(const char *s);
 extern void testingUtilFreeStrdup(char *s);
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/test/lib/thread.h b/test/lib/thread.h
index 6fa4b8b3..bb809edf 100644
--- a/test/lib/thread.h
+++ b/test/lib/thread.h
@@ -2,6 +2,10 @@
 
 #include <stdint.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 // I don't like this threading model, but let's use it for now so I can continue working
 
 typedef struct threadThread threadThread;
@@ -18,3 +22,7 @@ typedef uint64_t threadSysError;
 
 extern threadSysError threadNewThread(void (*f)(void *data), void *data, threadThread **t);
 extern threadSysError threadThreadWaitAndFree(threadThread *t);
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/test/lib/timer.h b/test/lib/timer.h
index 8094e5dd..78721385 100644
--- a/test/lib/timer.h
+++ b/test/lib/timer.h
@@ -3,6 +3,10 @@
 #include <stdbool.h>
 #include <stdint.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef int64_t timerDuration;
 typedef int64_t timerTime;
 
@@ -36,3 +40,7 @@ typedef uint64_t timerSysError;
 extern timerSysError timerRunWithTimeout(timerDuration d, void (*f)(void *data), void *data, bool *timedOut);
 
 extern timerSysError timerSleep(timerDuration d);
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/test/test.h b/test/test.h
index b91a1345..78d0616a 100644
--- a/test/test.h
+++ b/test/test.h
@@ -13,6 +13,10 @@
 #include "lib/thread.h"
 #include "lib/timer.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #define diff(fmt) "\ngot  " fmt "\nwant " fmt
 
 // main.c
@@ -36,17 +40,21 @@ extern void deferEventFree(testingT *t, void *data);
 extern testingSet *beforeTests;
 
 // errors.c
-extern void checkProgrammerErrorFull(testingT *t, const char *file, long line, const char *name, void (*f)(void *data), void *data, const char *msgWant, bool inThread);
-#define checkProgrammerError(t, name, f, data, msgWant) checkProgrammerErrorFull(t, __FILE__, __LINE__, name, f, data, msgWant, false)
-#define checkProgrammerErrorInThread(t, name, f, data, msgWant) checkProgrammerErrorFull(t, __FILE__, __LINE__, name, f, data, msgWant, true)
 struct checkErrorCase {
 	const char *name;
-	void (*f)(void *data);
+	void (*f)(void);
 	const char *msgWant;
 };
+extern void checkProgrammerErrorsFull(testingT *t, const char *file, long line, struct checkErrorCase *cases, bool inThread);
+#define checkProgrammerErrors(t, cases) checkProgrammerErrorsFull(t, __FILE__, __LINE__, cases, false)
+#define checkProgrammerErrorsInThread(t, cases) checkProgrammerErrorsFull(t, __FILE__, __LINE__, cases, true)
 
 // controls.c
 extern uiControlVtable *allocVtableFull(testingT *t, const char *file, long line);
 #define allocVtable(t) allocVtableFull(t, __FILE__, __LINE__)
 extern uiControlOSVtable *allocOSVtableFull(testingT *t, const char *file, long line);
 #define allocOSVtable(t) allocOSVtableFull(t, __FILE__, __LINE__)
+
+#ifdef __cplusplus
+}
+#endif