Ensure that null C strings do not break logging (#15255)

src/unittest/test_logging.cpp

@@ -0,0 +1,90 @@
+// SPDX-License-Identifier: LGPL-2.1-or-later
+
+#include "test.h"
+#include "log_internal.h"
+
+using std::ostream;
+
+class TestLogging : public TestBase
+{
+public:
+	TestLogging() { TestManager::registerTestModule(this); }
+	const char *getName() { return "TestLogging"; }
+
+	void runTests(IGameDef *gamedef);
+
+	void testNullChecks();
+	void testBitCheck();
+};
+
+static TestLogging g_test_instance;
+
+void TestLogging::runTests(IGameDef *gamedef)
+{
+	TEST(testNullChecks);
+	TEST(testBitCheck);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+void TestLogging::testNullChecks()
+{
+	CaptureLogOutput capture(g_logger);
+
+	infostream << "Test char*: "          << (char*)0          << std::endl;
+	infostream << "Test signed char*: "   << (signed char*)0   << std::endl;
+	infostream << "Test unsigned char*: " << (unsigned char*)0 << std::endl;
+
+	infostream << "Test const char*: "          << (const char*)0          << std::endl;
+	infostream << "Test const signed char*: "   << (const signed char*)0   << std::endl;
+	infostream << "Test const unsigned char*: " << (const unsigned char*)0 << std::endl;
+
+
+	auto logs = capture.take();
+	UASSERTEQ(size_t, logs.size(), 6);
+	UASSERTEQ(std::string, logs[0].text, "Test char*: (null)");
+	UASSERTEQ(std::string, logs[1].text, "Test signed char*: (null)");
+	UASSERTEQ(std::string, logs[2].text, "Test unsigned char*: (null)");
+	UASSERTEQ(std::string, logs[3].text, "Test const char*: (null)");
+	UASSERTEQ(std::string, logs[4].text, "Test const signed char*: (null)");
+	UASSERTEQ(std::string, logs[5].text, "Test const unsigned char*: (null)");
+}
+
+namespace {
+	class ForceEofBit {};
+	class ForceFailBit {};
+	class ForceBadBit {};
+
+	ostream& operator<<(ostream& os, ForceEofBit)
+	{
+		os.setstate(std::ios::eofbit);
+		return os;
+	}
+
+	ostream& operator<<(ostream& os, ForceFailBit)
+	{
+		os.setstate(std::ios::failbit);
+		return os;
+	}
+
+	ostream& operator<<(ostream& os, ForceBadBit)
+	{
+		os.setstate(std::ios::badbit);
+		return os;
+	}
+}
+
+void TestLogging::testBitCheck()
+{
+	CaptureLogOutput capture(g_logger);
+
+	infostream << "EOF is " << ForceEofBit{} << std::endl;
+	infostream << "Fail is " << ForceFailBit{} << std::endl;
+	infostream << "Bad is " << ForceBadBit{} << std::endl;
+
+	auto logs = capture.take();
+	UASSERTEQ(size_t, logs.size(), 3);
+	UASSERTEQ(std::string, logs[0].text, "EOF is (ostream:eofbit)");
+	UASSERTEQ(std::string, logs[1].text, "Fail is (ostream:failbit)");
+	UASSERTEQ(std::string, logs[2].text, "Bad is (ostream:badbit)");
+}