bit of testing, code improvements, formatting

src/laws.c

@@ -259,33 +259,28 @@ static void calculate_emigration(region * r)
 }
 
 
-static float peasant_luck_factor(void) {
-    static float factor = -1;
-
-    if (factor < 0)
-	get_param_int(global.parameters, "rules.peasants.peasantluck.factor", PEASANTLUCK);
-    return factor;
-}
-
-static float peasant_growth_factor(void) {
-    static float factor = -1;
-
-    if (factor < 0)
-	factor = get_param_flt(global.parameters, "rules.peasants.growth.factor", 
+static float peasant_growth_factor(void)
+{
+  return get_param_flt(global.parameters, "rules.peasants.growth.factor",
     0.0001F * PEASANTGROWTH);
-    return factor;
 }
 
-/** Bauern vermehren sich */
 #ifndef SLOWLUCK
-int peasant_luck_effect(int peasants, int luck, int maxp) {
-    int births=0;
-    double mean = _min(luck, peasants)
-	* peasant_luck_factor()
-	* peasant_growth_factor()
-	* ((peasants/(float)maxp < .9)?1:PEASANTFORCE);
+static float peasant_luck_factor(void)
+{
+  return get_param_int(global.parameters, "rules.peasants.peasantluck.factor",
+    PEASANTLUCK);
+}
 
-    births = RAND_ROUND(normalvariate(mean, mean/2+1));
+static
+int peasant_luck_effect(int peasants, int luck, int maxp, float variance)
+{
+  int births = 0;
+  double mean = _min(luck, peasants) * peasant_luck_factor()
+    * peasant_growth_factor() * ((peasants / (float)maxp < .9) ? 1 :
+      PEASANTFORCE);
+
+  births = RAND_ROUND(normalvariate(mean, variance * mean));
   if (births <= 0)
     births = 1;
   if (births > peasants / 2)
@@ -294,8 +289,9 @@ int peasant_luck_effect(int peasants, int luck, int maxp) {
 }
 
 #else
-int peasant_luck_effect(int peasants, int luck, int maxp) {
+int peasant_luck_effect(int peasants, int luck, int maxp, float variance) {
   int n, births=0;
+  float factor = peasant_growth_factor();
   for (n = peasants; n && luck; --n) {
     int chances = 0;
 
@@ -305,7 +301,7 @@ int peasant_luck_effect(int peasants, int luck, int maxp) {
     }
 
     while (chances--) {
-	    if (rng_double() < peasant_growth_factor()) {
+      if (rng_double() < factor) {
         /* Only raise with 75% chance if peasants have
          * reached 90% of maxpopulation */
         if (peasants / (float)maxp < 0.9 || chance(PEASANTFORCE)) {
@@ -336,7 +332,7 @@ static void peasants(region * r)
             luck = a->data.i * 1000;
         }
 
-	luck = peasant_luck_effect(peasants, luck, maxp);
+        luck = peasant_luck_effect(peasants, luck, maxp, .5);
         ADDMSG(&r->msgs, msg_message("peasantluck_success", "births", luck));
 
         peasants += births + luck;

src/laws.test.c

@@ -1,5 +1,5 @@
 #include <platform.h>
-#include "laws.h"
+#include "laws.c"
 
 #include <kernel/ally.h>
 #include <kernel/config.h>
@@ -692,6 +692,32 @@ static void test_reserve_self(CuTest *tc) {
     test_cleanup();
 }
 
+static void statistic_test(CuTest *tc, int peasants, int luck, int maxp,
+  float variance, int min_value, int max_value)
+{
+  int effect, i;
+  for (i = 0; i < 1000; ++i) {
+    effect = peasant_luck_effect(peasants, luck, maxp, variance);
+    CuAssertTrue(tc, min_value <= effect);
+    CuAssertTrue(tc, max_value >= effect);
+  }
+}
+
+static void test_peasant_luck_effect(CuTest *tc)
+{
+
+  set_param(&global.parameters, "rules.peasants.peasantluck.factor", "10");
+  set_param(&global.parameters, "rules.peasants.growth.factor", "0.001");
+
+  statistic_test(tc, 100, 2, 1000, 0, 1, 1);
+  statistic_test(tc, 1000, 400, 1000, 0, 400 * 10 * 0.001 * .75,
+    400 * 10 * 0.001 * .75);
+  statistic_test(tc, 1000, 1000, 2000, .5, 1, 501);
+
+  set_param(&global.parameters, "rules.peasants.growth.factor", "1");
+  statistic_test(tc, 1000, 1000, 1000, 0, 501, 501);
+}
+
 CuSuite *get_laws_suite(void)
 {
     CuSuite *suite = CuSuiteNew();
@@ -722,6 +748,7 @@ CuSuite *get_laws_suite(void)
     SUITE_ADD_TEST(suite, test_force_leave_buildings);
     SUITE_ADD_TEST(suite, test_force_leave_ships);
     SUITE_ADD_TEST(suite, test_force_leave_ships_on_ocean);
+    SUITE_ADD_TEST(suite, test_peasant_luck_effect);
 
     return suite;
 }