From 83d40962d205c34c5abc1d2e58363dac593608ed Mon Sep 17 00:00:00 2001
From: Enno Rehling <enno@eressea.de>
Date: Tue, 2 May 2017 08:45:18 +0200
Subject: [PATCH] disable randomness that causes some tests to become
 intermittent. fix normalvariante and chance so they work better with constant
 rng always returning zero

---
 scripts/run-tests-e2.lua     | 1 +
 scripts/run-tests-e3.lua     | 1 +
 scripts/tests/common.lua     | 3 +++
 scripts/tests/production.lua | 1 +
 src/bindings.c               | 7 +++++++
 src/util/rand.c              | 4 ++--
 6 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/scripts/run-tests-e2.lua b/scripts/run-tests-e2.lua
index 4a2b3e59e..67a534ae6 100644
--- a/scripts/run-tests-e2.lua
+++ b/scripts/run-tests-e2.lua
@@ -17,6 +17,7 @@ require 'eressea.path'
 require 'tests.e2'
 require 'lunit'
 
+rng_default(0)
 rules = require('eressea.' .. config.rules)
 result = lunit.main()
 return result.errors + result.failed
diff --git a/scripts/run-tests-e3.lua b/scripts/run-tests-e3.lua
index 47bcca60b..241b3e9fd 100644
--- a/scripts/run-tests-e3.lua
+++ b/scripts/run-tests-e3.lua
@@ -17,6 +17,7 @@ require 'eressea.xmlconf'
 require 'tests.e3'
 require 'lunit'
 
+rng_default(0)
 eressea.settings.set("rules.alliances", "0")
 rules = require('eressea.' .. config.rules)
 result = lunit.main()
diff --git a/scripts/tests/common.lua b/scripts/tests/common.lua
index 08a7ca94f..e612a17d7 100644
--- a/scripts/tests/common.lua
+++ b/scripts/tests/common.lua
@@ -218,6 +218,9 @@ function test_gmtool()
     local r1 = region.create(1, 0, "plain")
     local r2 = region.create(1, 1, "plain")
     local r3 = region.create(1, 2, "plain")
+    if not gmtool then
+        return
+    end
     gmtool.open()
     gmtool.select(r1, true)
     gmtool.select_at(0, 1, true)
diff --git a/scripts/tests/production.lua b/scripts/tests/production.lua
index b470a2652..8727762d1 100644
--- a/scripts/tests/production.lua
+++ b/scripts/tests/production.lua
@@ -6,6 +6,7 @@ function setup()
     eressea.game.reset()
     eressea.settings.set("rules.food.flags", "4") -- food is free
     eressea.settings.set("NewbieImmunity", "0")
+    eressea.settings.set("study.random_progress", "0")
 end
 
 local function create_faction(race)
diff --git a/src/bindings.c b/src/bindings.c
index 9ea548465..d78ed8537 100755
--- a/src/bindings.c
+++ b/src/bindings.c
@@ -990,6 +990,12 @@ static void parse_inifile(lua_State * L, const dictionary * d, const char *secti
     }
 }
 
+static int lua_rng_default(lua_State *L) {
+    UNUSED_ARG(L);
+    random_source_inject_constant(0);
+    return 0;
+}
+
 void tolua_bind_open(lua_State * L);
 
 int tolua_bindings_open(lua_State * L, const dictionary *inifile)
@@ -1060,6 +1066,7 @@ int tolua_bindings_open(lua_State * L, const dictionary *inifile)
         tolua_function(L, TOLUA_CAST "get_ship", tolua_get_ship);
         tolua_function(L, TOLUA_CAST "get_building", tolua_get_building);
         tolua_function(L, TOLUA_CAST "get_region", tolua_get_region);
+	tolua_function(L, TOLUA_CAST "rng_default", lua_rng_default);
         tolua_function(L, TOLUA_CAST "factions", tolua_get_factions);
         tolua_function(L, TOLUA_CAST "regions", tolua_get_regions);
         tolua_function(L, TOLUA_CAST "read_turn", tolua_read_turn);
diff --git a/src/util/rand.c b/src/util/rand.c
index f5c8a28bc..584e8541e 100644
--- a/src/util/rand.c
+++ b/src/util/rand.c
@@ -46,7 +46,7 @@ double normalvariate(double mu, double sigma)
     double z;
     for (;;) {
         double u1 = rng_double();
-        double u2 = 1.0 - rng_double();
+        double u2 = rng_double();
         z = NV_MAGICCONST * (u1 - 0.5) / u2;
         if (z * z / 4.0 <= -log(u2)) {
             break;
@@ -73,7 +73,7 @@ bool chance(double x)
 {
     if (x >= 1.0)
         return true;
-    return rng_double() < x;
+    return (1-rng_double()) < x;
 }
 
 typedef struct random_source {