diff --git a/Northstar.Custom/mod.json b/Northstar.Custom/mod.json
index 399311e43..69432f498 100644
--- a/Northstar.Custom/mod.json
+++ b/Northstar.Custom/mod.json
@@ -440,6 +440,19 @@
 			"Path": "sh_northstar_safe_io.gnut",
 			"RunOn": "CLIENT || SERVER || UI"
 		},
+		{
+			"Path": "_testing.nut",
+			"RunOn": "CLIENT || SERVER || UI",
+			"ClientCallback": {
+				"Before": "Testing_Init"
+			},
+			"ServerCallback": {
+				"Before": "Testing_Init"
+			},
+			"UICallback": {
+				"Before": "Testing_Init"
+			}
+		},
 		{
 			"Path": "_event_models.gnut",
 			"RunOn": "SERVER && LOBBY",
diff --git a/Northstar.Custom/mod/scripts/vscripts/_testing.nut b/Northstar.Custom/mod/scripts/vscripts/_testing.nut
new file mode 100644
index 000000000..15bcf18ba
--- /dev/null
+++ b/Northstar.Custom/mod/scripts/vscripts/_testing.nut
@@ -0,0 +1,302 @@
+global function Testing_Init
+global function RunAllTests
+global function RunAllTests_SaveToFile
+global function RunTestsByCategory
+global function RunTestByCategoryAndName
+
+global function AddTest
+
+struct TestInfo
+{
+	string testName
+	var functionref() callback
+	// whether the test completed successfully
+	// if this is true, actualResult is valid
+	bool completed
+	// var not string because then i can just set it to an exception
+	// which print can then handle
+	var error
+	// whether the test is considered successful
+	var expectedResult
+	var actualResult
+	bool passed
+}
+
+struct {
+	table< string, array< TestInfo > > tests = {}
+} file
+
+void function Testing_Init()
+{
+	// tests for the testing functions :)
+	//AddTest( "Example Tests", "example succeeding test", ExampleTest_ReturnsTrue, true )
+	//AddTest( "Example Tests", "example failing test", ExampleTest_ReturnsFalse, true )
+	//AddTest( "Example Tests", "example erroring test", ExampleTest_ThrowsError, true )
+	//AddTest( "Example Tests", "example test with args", var function() {
+	//	return ExampleTest_HasArgs_ReturnsNonVar( 2, 3 )
+	//}, 6 )
+}
+
+int function ExampleTest_HasArgs_ReturnsNonVar( int first, int second )
+{
+	return first * second
+}
+
+var function ExampleTest_ReturnsFalse()
+{
+	return false
+}
+
+var function ExampleTest_ReturnsTrue()
+{
+	return true
+}
+
+var function ExampleTest_ThrowsError()
+{
+	throw "Example exception"
+	return null
+}
+
+void function RunAllTests_SaveToFile()
+{
+	RunAllTests()
+
+	#if UI
+	string fileName = "ns-unit-tests-UI.json"
+	#elseif CLIENT
+	string fileName = "ns-unit-tests-CLIENT.json"
+	#elseif SERVER
+	string fileName = "ns-unit-tests-SERVER.json"
+	#endif
+
+	// cant encode structs so have to reconstruct a table manually from the structs
+	table out = {}
+	foreach ( category, tests in file.tests )
+	{
+		array categoryResults = []
+		foreach ( test in tests )
+		{
+			table testTable = {}
+			testTable[ "name" ] <- test.testName
+			testTable[ "completed" ] <- test.completed
+			testTable[ "passed" ] <- test.passed
+			if ( !test.completed )
+				testTable[ "error" ] <- test.error
+			else if ( !test.passed )
+			{
+				testTable[ "expectedResult" ] <- test.expectedResult
+				testTable[ "actualResult" ] <- test.actualResult
+			}
+
+			categoryResults.append( testTable )
+		}
+		out[ category ] <- categoryResults
+	}
+
+	NSSaveJSONFile( fileName, out )
+}
+
+void function RunAllTests()
+{
+	printt( "Running all tests!" )
+
+	foreach ( category, categoryTests in file.tests )
+	{
+		foreach ( test in categoryTests )
+		{
+			RunTest( test )
+		}
+	}
+
+	PrintAllTestResults()
+}
+
+void function RunTestsByCategory( string category )
+{
+	if ( !( category in file.tests ) )
+	{
+		printt( format( "Category '%s' has no tests registered", category ) )
+		return
+	}
+
+	foreach ( categoryTest in file.tests[ category ] )
+	{
+		RunTest( categoryTest )
+	}
+}
+
+void function RunTestByCategoryAndName( string category, string testName )
+{
+	// find test
+	if ( !( category in file.tests ) )
+	{
+		printt( format( "Category '%s' has no tests registered", category ) )
+		return
+	}
+
+	TestInfo ornull foundTest = null
+	foreach ( categoryTest in file.tests[ category ] )
+	{
+		if ( categoryTest.testName == testName )
+		{
+			foundTest = categoryTest
+			break
+		}
+	}
+
+	if ( !foundTest )
+	{
+		printt( format( "Category '%s' does not contain a test with name '%s'", category, testName ) )
+		return
+	}
+
+	expect TestInfo( foundTest )
+	
+	printt( "Running test!" )
+	// run test
+	RunTest( foundTest )
+	// print result
+	PrintTestResult( foundTest )
+}
+
+void function RunTest( TestInfo test )
+{
+	test.completed = false
+	test.passed = false
+	test.actualResult = null
+	test.error = ""
+
+	try
+	{
+		test.actualResult = test.callback()
+		test.completed = true
+		test.passed = test.actualResult == test.expectedResult
+	}
+	catch ( exception )
+	{
+		test.completed = false
+		test.error = exception
+	}
+}
+
+void function PrintAllTestResults()
+{
+	int totalSucceeded = 0
+	int totalFailed = 0
+	int totalErrored = 0
+
+	foreach ( category, categoryTests in file.tests )
+	{
+		int categorySucceeded = 0
+		int categoryFailed = 0
+		int categoryErrored = 0
+
+		printt( format( "Results for category: '%s'", category ) )
+		foreach ( test in categoryTests )
+		{
+			if ( test.completed )
+			{
+				if ( test.passed )
+				{
+					printt( "\t", test.testName, "- Passed!" )
+					categorySucceeded++
+				}
+				else
+				{
+					printt( "\t", test.testName, "- Failed!" )
+					printt( "\t\tExpected:", test.expectedResult )
+					printt( "\t\tActual:  ", test.actualResult )
+					categoryFailed++
+				}
+			}
+			else
+			{
+				printt( "\t", test.testName, "- Errored!" )
+				printt( "\t\tError:", test.error )
+				categoryErrored++
+			}
+		}
+
+		printt( "Succeeded:", categorySucceeded, "Failed:", categoryFailed, "Errored:", categoryErrored )
+
+		totalSucceeded += categorySucceeded
+		totalFailed += categoryFailed
+		totalErrored += categoryErrored
+	}
+
+	printt( "TOTAL SUCCEEDED:", totalSucceeded, "TOTAL FAILED:", totalFailed, "TOTAL ERRORED:", totalErrored )
+}
+
+void function PrintCategoryResults( string category )
+{
+	int categorySucceeded = 0
+	int categoryFailed = 0
+	int categoryErrored = 0
+
+	printt( format( "Results for category: '%s'", category ) )
+	foreach ( test in file.tests[ category ] )
+	{
+		if ( test.completed )
+		{
+			if ( test.passed )
+			{
+				printt( "\t", test.testName, "- Passed!" )
+				categorySucceeded++
+			}
+			else
+			{
+				printt( "\t", test.testName, "- Failed!" )
+				printt( "\t\tExpected:", test.expectedResult )
+				printt( "\t\tActual:  ", test.actualResult )
+				categoryFailed++
+			}
+		}
+		else
+		{
+			printt( "\t", test.testName, "- Errored!" )
+			printt( "\t\tError:", test.error )
+			categoryErrored++
+		}
+	}
+
+	printt( "Succeeded:", categorySucceeded, "Failed:", categoryFailed, "Errored:", categoryErrored )
+}
+
+void function PrintTestResult( TestInfo test )
+{
+	string resultString = test.testName
+
+	if ( test.completed )
+	{
+		if ( test.passed )
+			resultString += " - Passed!"
+		else
+		{
+			resultString += " - Failed!"
+			resultString += "\n\tExpected: " + test.expectedResult
+			resultString += "\n\tActual:   " + test.actualResult
+		}
+	}
+	else
+	{
+		resultString += " - Not completed!"
+		resultString += "\n\tError: " + test.error
+	}
+
+	printt( resultString )
+}
+
+void function AddTest( string testCategory, string testName, var functionref() testFunc, var expectedResult )
+{
+	TestInfo newTest
+	newTest.testName = testName
+	newTest.callback = testFunc
+	newTest.expectedResult = expectedResult
+
+	// create the test category if it doesn't exist
+	if ( !( testCategory in file.tests ) )
+		file.tests[ testCategory ] <- [ newTest ]
+	else
+		file.tests[ testCategory ].append( newTest )
+}