Description: Fix unit tests to be run standalone
 For the unittests, upstream "bakes in" the build directory path, via
 ${CMAKE_CURRENT_SOURCE_DIR} to locate the resources required by the tests.
 This patch replaces the fixed path by a relative path to the src directory,
 and allows one to override them using environment variables.
 .
 The downside is, that now the unittests have to either specify the environment
 variables or be run from the top level source dir.
 .
 The upside is, that autopkgtest will work without recompiling.
Author: Tobias Frost <tobi@debian.org>
Forwarded: PARTLY forwarded https://github.com/minetest/minetest/pull/12801
 
Last-Update: 2022-09-16 <YYYY-MM-DD, last update of the meta-information, optional>
---
This patch header follows DEP-3: http://dep.debian.net/deps/dep3/
--- a/src/unittest/test_servermodmanager.cpp
+++ b/src/unittest/test_servermodmanager.cpp
@@ -24,6 +24,8 @@
 #include "test_config.h"
 #include "util/string.h"
 
+#include <stdlib.h>
+
 class TestServerModManager : public TestBase
 {
 public:
@@ -61,8 +63,16 @@
 		_putenv(mod_path.c_str());
 	}
 #else
-	setenv("MINETEST_SUBGAME_PATH", TEST_SUBGAME_PATH, 1);
-	setenv("MINETEST_MOD_PATH", TEST_MOD_PATH, 1);
+	if(!getenv("TEST_SUBGAME_PATH")) {
+	    setenv("MINETEST_SUBGAME_PATH", TEST_SUBGAME_PATH, 1);
+	} else {
+	    setenv("MINETEST_SUBGAME_PATH", getenv("TEST_SUBGAME_PATH"), 1);
+	}
+	if(!getenv("TEST_MOD_PATH")) {
+	    setenv("MINETEST_MOD_PATH", TEST_MOD_PATH, 1);
+	} else {
+	    setenv("MINETEST_MOD_PATH", getenv("TEST_MOD_PATH"), 1);
+	}
 #endif
 
 	TEST(testCreation);
@@ -103,6 +113,10 @@
 void TestServerModManager::testCreation()
 {
 	std::string path = std::string(TEST_WORLDDIR) + DIR_DELIM + "world.mt";
+	if (getenv("TEST_WORLDDIR")) {
+	    path = getenv("TEST_WORLDDIR");
+	    path = path + DIR_DELIM + "world.mt";
+	}
 	Settings world_config;
 	world_config.set("gameid", "devtest");
 	world_config.set("load_mod_test_mod", "true");
@@ -131,7 +145,12 @@
 
 void TestServerModManager::testGetMods()
 {
-	ServerModManager sm(std::string(TEST_WORLDDIR));
+    std::string path = std::string(TEST_WORLDDIR);
+    if (getenv("TEST_WORLDDIR")) {
+        path = getenv("TEST_WORLDDIR");
+    }
+
+	ServerModManager sm(path);
 	const auto &mods = sm.getMods();
 	UASSERTEQ(bool, mods.empty(), false);
 
@@ -155,7 +174,11 @@
 
 void TestServerModManager::testGetModspec()
 {
-	ServerModManager sm(std::string(TEST_WORLDDIR));
+    std::string path = std::string(TEST_WORLDDIR);
+    if (getenv("TEST_WORLDDIR")) {
+        path = getenv("TEST_WORLDDIR");
+    }
+	ServerModManager sm(path);
 	UASSERTEQ(const ModSpec *, sm.getModSpec("wrongmod"), NULL);
 	UASSERT(sm.getModSpec("basenodes") != NULL);
 }
@@ -170,7 +193,11 @@
 
 void TestServerModManager::testGetModNames()
 {
-	ServerModManager sm(std::string(TEST_WORLDDIR));
+    std::string path = std::string(TEST_WORLDDIR);
+    if (getenv("TEST_WORLDDIR")) {
+        path = getenv("TEST_WORLDDIR");
+    }
+	ServerModManager sm(path);
 	std::vector<std::string> result;
 	sm.getModNames(result);
 	UASSERTEQ(bool, result.empty(), false);
@@ -187,10 +214,14 @@
 
 void TestServerModManager::testGetModMediaPaths()
 {
-	ServerModManager sm(std::string(TEST_WORLDDIR));
+    std::string path = std::string(TEST_WORLDDIR);
+    if (getenv("TEST_WORLDDIR")) {
+        path = getenv("TEST_WORLDDIR");
+    }
+	ServerModManager sm(path);
 	std::vector<std::string> result;
 	sm.getModsMediaPaths(result);
-	UASSERTEQ(bool, result.empty(), false);
+    UASSERTEQ(bool, result.empty(), false);
 
 	// Test media overriding:
 	// unittests depends on basenodes to override default_dirt.png,
--- a/src/unittest/CMakeLists.txt
+++ b/src/unittest/CMakeLists.txt
@@ -45,9 +45,9 @@
 	${CMAKE_CURRENT_SOURCE_DIR}/test_keycode.cpp
 	PARENT_SCOPE)
 
-set (TEST_WORLDDIR ${CMAKE_CURRENT_SOURCE_DIR}/test_world)
-set (TEST_SUBGAME_PATH ${CMAKE_CURRENT_SOURCE_DIR}/../../games/devtest)
-set (TEST_MOD_PATH ${CMAKE_CURRENT_SOURCE_DIR}/test_mod)
+set (TEST_WORLDDIR src/unittest/test_world)
+set (TEST_SUBGAME_PATH games/devtest)
+set (TEST_MOD_PATH src/unittest/test_mod)
 
 configure_file(
 	"${CMAKE_CURRENT_SOURCE_DIR}/test_config.h.in"