More desirable sorting of tests: by line number per file, specifically. Also per-file, but that can remain unguaranteed if I ever spin this out into its own library.

test/testing.c

@@ -2,6 +2,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <setjmp.h>
+#include <string.h>
 #include "testing.h"
 
 #define testingprivNew(T) ((T *) malloc(sizeof (T)))
@@ -79,6 +80,27 @@ void testingprivRegisterTestAfter(const char *name, void (*f)(testingT *), const
 	testsetAdd(&testsAfter, name, f, file, line);
 }
 
+static int testcmp(const void *a, const void *b)
+{
+	const testingT *ta = (const testingT *) a;
+	const testingT *tb = (const testingT *) b;
+	int ret;
+
+	ret = strcmp(ta->file, tb->file);
+	if (ret != 0)
+		return ret;
+	if (ta->line < tb->line)
+		return -1;
+	if (ta->line > tb->line)
+		return 1;
+	return 0;
+}
+
+static void testsetSort(struct testset *set)
+{
+	qsort(set->tests, set->len, sizeof (testingT), testcmp);
+}
+
 static void runDefers(testingT *t)
 {
 	struct defer *d;
@@ -126,6 +148,10 @@ int testingMain(void)
 		return 0;
 	}
 
+	testsetSort(&testsBefore);
+	testsetSort(&tests);
+	testsetSort(&testsAfter);
+
 	anyFailed = 0;
 	testsetRun(&testsBefore, &anyFailed);
 	testsetRun(&tests, &anyFailed);

test/testing.h

@@ -1,9 +1,5 @@
 // 27 february 2018
 
-// TODO
-// - https://blogs.msdn.microsoft.com/oldnewthing/20181107-00/?p=100155 https://blogs.msdn.microsoft.com/oldnewthing/20181108-00/?p=100165 https://blogs.msdn.microsoft.com/oldnewthing/20181109-00/?p=100175
-// - also in the above: note the unspecified order of data in the sub-segments...
-
 #include <stdarg.h>
 
 #define testingprivImplName(basename) testingprivImpl ## basename