Fix TestLogger not updating severity by itself

MinSeverity only gets updated if the logger is already active, so
we have to set severity after the logger has been activated.

Also add a Clear() method to clear existing log messages and
assert macros to assert both the existence and absence of a pattern
in the log.

Author: jschmidt-icinga

test/base-testloggerfixture.hpp

@@ -10,6 +10,12 @@
 #include <boost/test/test_tools.hpp>
 #include <future>
 
+#define CHECK_LOG_MESSAGE(pattern, timeout) BOOST_CHECK(ExpectLogPattern(pattern, timeout))
+#define REQUIRE_LOG_MESSAGE(pattern, timeout) BOOST_REQUIRE(ExpectLogPattern(pattern, timeout))
+
+#define CHECK_NO_LOG_MESSAGE(pattern, timeout) BOOST_CHECK(!ExpectLogPattern(pattern, timeout))
+#define REQUIRE_NO_LOG_MESSAGE(pattern, timeout) BOOST_REQUIRE(!ExpectLogPattern(pattern, timeout))
+
 namespace icinga {
 
 class TestLogger : public Logger
@@ -52,6 +58,13 @@ class TestLogger : public Logger
 		return ret;
 	}
 
+	void Clear()
+	{
+		std::unique_lock lock(m_Mutex);
+		m_Expects.clear();
+		m_LogEntries.clear();
+	}
+
 private:
 	void ProcessLogEntry(const LogEntry& entry) override
 	{
@@ -87,9 +100,9 @@ struct TestLoggerFixture
 {
 	TestLoggerFixture()
 	{
-		testLogger->SetSeverity(testLogger->SeverityToString(LogDebug));
 		testLogger->Activate(true);
 		testLogger->SetActive(true);
+		testLogger->SetSeverity(TestLogger::SeverityToString(LogDebug));
 	}
 
 	~TestLoggerFixture()