Merge branch 'mr/124' into maint-0.4.4

src/test/testing_common.c

@@ -286,6 +286,8 @@ main(int c, const char **v)
   /* Don't add default logs; the tests manage their own. */
   quiet_level = QUIET_SILENT;
 
+  unsigned num=1, den=1;
+
   for (i_out = i = 1; i < c; ++i) {
     if (!strcmp(v[i], "--warn")) {
       loglevel = LOG_WARN;
@@ -297,6 +299,19 @@ main(int c, const char **v)
       loglevel = LOG_DEBUG;
     } else if (!strcmp(v[i], "--accel")) {
       accel_crypto = 1;
+    } else if (!strcmp(v[i], "--fraction")) {
+      if (i+1 == c) {
+        printf("--fraction needs an argument.\n");
+        return 1;
+      }
+      const char *fracstr = v[++i];
+      char ch;
+      if (sscanf(fracstr, "%u/%u%c", &num, &den, &ch) != 2) {
+        printf("--fraction expects a fraction as an input.\n");
+      }
+      if (den == 0 || num == 0 || num > den) {
+        printf("--fraction expects a valid fraction as an input.\n");
+      }
     } else {
       v[i_out++] = v[i];
     }
@@ -373,6 +388,33 @@ main(int c, const char **v)
     smartlist_free(skip);
   }
 
+  if (den != 1) {
+    // count the tests. Linear but fast.
+    unsigned n_tests = 0;
+    struct testgroup_t *tg;
+    struct testcase_t *tc;
+    for (tg = testgroups; tg->prefix != NULL; ++tg) {
+      for (tc = tg->cases; tc->name != NULL; ++tc) {
+        ++n_tests;
+      }
+    }
+    // Which tests should we run?  This can give iffy results if den is huge
+    // but it doesn't actually matter in practice.
+    unsigned tests_per_chunk = CEIL_DIV(n_tests, den);
+    unsigned start_at = (num-1) * tests_per_chunk;
+
+    // Skip the tests that are outside of the range.
+    unsigned idx = 0;
+    for (tg = testgroups; tg->prefix != NULL; ++tg) {
+      for (tc = tg->cases; tc->name != NULL; ++tc) {
+        if (idx < start_at || idx >= start_at + tests_per_chunk) {
+          tc->flags |= TT_SKIP;
+        }
+        ++idx;
+      }
+    }
+  }
+
   int have_failed = (tinytest_main(c, v, testgroups) != 0);
 
   free_pregenerated_keys();