Move TestGameDef to test.h header

This makes the test gamedef available to all test modules. I removed an
unused include from test.h and included some stuff we use in test.h,
since I had to modify the include list anyway for the change.

src/unittest/test.cpp

@@ -32,25 +32,6 @@ content_t t_CONTENT_BRICK;
 //// TestGameDef
 ////
 
-class TestGameDef : public DummyGameDef {
-public:
-	TestGameDef();
-	~TestGameDef() = default;
-
-	void defineSomeNodes();
-
-	bool joinModChannel(const std::string &channel);
-	bool leaveModChannel(const std::string &channel);
-	bool sendModChannelMessage(const std::string &channel, const std::string &message);
-	ModChannel *getModChannel(const std::string &channel)
-	{
-		return m_modchannel_mgr->getModChannel(channel);
-	}
-
-private:
-	std::unique_ptr<ModChannelMgr> m_modchannel_mgr;
-};
-
 
 TestGameDef::TestGameDef() :
 	DummyGameDef(),

src/unittest/test.h

@@ -4,15 +4,21 @@
 
 #pragma once
 
-#include <functional>
-#include <exception>
-#include <sstream>
-#include <vector>
-
+#include "dummygamedef.h"
 #include "irrlichttypes_bloated.h"
-#include "porting.h"
 #include "filesys.h"
 #include "mapnode.h"
+#include "modchannels.h"
+#include "porting.h"
+
+#include <cstdio>
+#include <functional>
+#include <iostream>
+#include <memory>
+#include <sstream>
+#include <string>
+#include <utility>
+#include <vector>
 
 class TestFailedException { // don’t derive from std::exception to avoid accidental catch
 public:
@@ -105,6 +111,25 @@ public:
 	}
 };
 
+class TestGameDef : public DummyGameDef {
+public:
+	TestGameDef();
+	~TestGameDef() = default;
+
+	void defineSomeNodes();
+
+	bool joinModChannel(const std::string &channel);
+	bool leaveModChannel(const std::string &channel);
+	bool sendModChannelMessage(const std::string &channel, const std::string &message);
+	ModChannel *getModChannel(const std::string &channel)
+	{
+		return m_modchannel_mgr->getModChannel(channel);
+	}
+
+private:
+	std::unique_ptr<ModChannelMgr> m_modchannel_mgr;
+};
+
 // A few item and node definitions for those tests that need them
 extern content_t t_CONTENT_STONE;
 extern content_t t_CONTENT_GRASS;