Index: src/test/OTAppDelegate.m
==================================================================
--- src/test/OTAppDelegate.m
+++ src/test/OTAppDelegate.m
@@ -145,11 +145,11 @@
 	padConfigureInput(1, HidNpadStyleSet_NpadStandard);
 	updateConsole(true);
 #endif
 }
 
-- (OFSet OF_GENERIC(Class) *)testClasses
+- (OFMutableSet OF_GENERIC(Class) *)testClasses
 {
 	Class *classes = objc_copyClassList(NULL);
 	OFMutableSet *testClasses;
 
 	if (classes == NULL)
@@ -180,11 +180,10 @@
 		OFFreeMemory(classes);
 	}
 
 	[testClasses removeObject: [OTTestCase class]];
 
-	[testClasses makeImmutable];
 	return testClasses;
 }
 
 - (OFSet OF_GENERIC(OFValue *) *)testsInClass: (Class)class
 {
@@ -400,16 +399,36 @@
 	return description;
 }
 
 - (void)applicationDidFinishLaunching: (OFNotification *)notification
 {
-	OFSet OF_GENERIC(Class) *testClasses = [self testClasses];
+	OFMutableSet OF_GENERIC(Class) *testClasses;
 	size_t numSucceeded = 0, numFailed = 0, numSkipped = 0;
 	OFMutableDictionary *summaries = [OFMutableDictionary dictionary];
+
+	if ([OFApplication arguments].count > 0) {
+		testClasses = [OFMutableSet set];
+
+		for (OFString *className in [OFApplication arguments]) {
+			Class class = objc_lookUpClass([className
+			    cStringWithEncoding: OFStringEncodingASCII]);
+
+			if (class == Nil ||
+			    !isSubclassOfClass(class, [OTTestCase class])) {
+				[OFStdErr writeFormat: @"%@ is not a valid "
+						       @"test case!\n",
+						       className];
+				[OFApplication terminateWithStatus: 1];
+			}
+
+			[testClasses addObject: class];
+		}
+	} else
+		testClasses = [self testClasses];
 
 	[OFStdOut setForegroundColor: [OFColor purple]];
-	[OFStdOut writeString: @"Found "];
+	[OFStdOut writeString: @"Running "];
 #if !defined(OF_WII) && !defined(OF_NINTENDO_DS) && \
     !defined(OF_NINTENDO_3DS) && !defined(OF_NINTENDO_SWITCH)
 	[OFStdOut setForegroundColor: [OFColor fuchsia]];
 #endif
 	[OFStdOut writeFormat: @"%zu", testClasses.count];

Index: tests/Makefile
==================================================================
--- tests/Makefile
+++ tests/Makefile
@@ -145,11 +145,11 @@
 	LD_LIBRARY_PATH=.$${LD_LIBRARY_PATH+:}$$LD_LIBRARY_PATH \
 	DYLD_FRAMEWORK_PATH=../src:../src/runtime$${DYLD_FRAMEWORK_PATH+:}$$DYLD_FRAMEWORK_PATH \
 	DYLD_LIBRARY_PATH=.$${DYLD_LIBRARY_PATH+:}$$DYLD_LIBRARY_PATH \
 	LIBRARY_PATH=.$${LIBRARY_PATH+:}$$LIBRARY_PATH \
 	ASAN_OPTIONS=allocator_may_return_null=1 \
-	${WRAPPER} ./${PROG_NOINST}; EXIT=$$?; \
+	${WRAPPER} ./${PROG_NOINST} ${TESTCASES}; EXIT=$$?; \
 	rm -f libobjfw.so.${OBJFW_LIB_MAJOR}; \
 	rm -f libobjfw.so.${OBJFW_LIB_MAJOR_MINOR}; \
 	rm -f objfw${OBJFW_LIB_MAJOR}.dll; \
 	rm -f libobjfw.${OBJFW_LIB_MAJOR}.dylib; \
 	rm -f libobjfwrt.so.${OBJFWRT_LIB_MAJOR}; \