Fix flaky PION_LOG_*, more tests (#117)

#### Description

I was tracking an issue with video feedback when I noticed the logs were
flaky. Initially, I thought it was a bug, but I later discovered that
PION_LOG_*=all is unreliable due to how the range map is ordered.

Added tests to cover everything.

logger.go

@@ -213,7 +213,9 @@ func NewDefaultLoggerFactory() *DefaultLoggerFactory {
 		}
 
 		if strings.ToLower(env) == "all" {
-			factory.DefaultLogLevel = level
+			if factory.DefaultLogLevel < level {
+				factory.DefaultLogLevel = level
+			}
 
 			continue
 		}

logging_test.go

@@ -79,6 +79,50 @@ func testErrorLevel(t *testing.T, logger *logging.DefaultLeveledLogger) {
 	}
 }
 
+func testTraceLevel(t *testing.T, logger *logging.DefaultLeveledLogger) {
+	t.Helper()
+
+	var outBuf bytes.Buffer
+	logger.WithOutput(&outBuf)
+
+	traceMsg := "trace message"
+	logger.Trace(traceMsg)
+	if !strings.Contains(outBuf.String(), traceMsg) {
+		t.Errorf("Expected to find %q in %q, but didn't", traceMsg, outBuf.String())
+	}
+	logger.Tracef(traceMsg) // nolint: govet
+	if !strings.Contains(outBuf.String(), traceMsg) {
+		t.Errorf("Expected to find %q in %q, but didn't", traceMsg, outBuf.String())
+	}
+}
+
+func testInfoLevel(t *testing.T, logger *logging.DefaultLeveledLogger) {
+	t.Helper()
+
+	var outBuf bytes.Buffer
+	logger.WithOutput(&outBuf)
+
+	infoMsg := "info message"
+	logger.Info(infoMsg)
+	if !strings.Contains(outBuf.String(), infoMsg) {
+		t.Errorf("Expected to find %q in %q, but didn't", infoMsg, outBuf.String())
+	}
+	logger.Infof(infoMsg) // nolint: govet
+	if !strings.Contains(outBuf.String(), infoMsg) {
+		t.Errorf("Expected to find %q in %q, but didn't", infoMsg, outBuf.String())
+	}
+}
+
+func testAllLevels(t *testing.T, logger *logging.DefaultLeveledLogger) {
+	t.Helper()
+
+	testDebugLevel(t, logger)
+	testWarnLevel(t, logger)
+	testErrorLevel(t, logger)
+	testTraceLevel(t, logger)
+	testInfoLevel(t, logger)
+}
+
 func TestDefaultLoggerFactory(t *testing.T) {
 	factory := logging.DefaultLoggerFactory{
 		Writer:          os.Stderr,
@@ -115,6 +159,96 @@ func TestDefaultLogger(t *testing.T) {
 	testErrorLevel(t, logger)
 }
 
+func TestNewDefaultLoggerFactory(t *testing.T) {
+	factory := logging.NewDefaultLoggerFactory()
+
+	disabled := factory.NewLogger("DISABLE")
+	errorLevel := factory.NewLogger("ERROR")
+	warnLevel := factory.NewLogger("WARN")
+	infoLevel := factory.NewLogger("INFO")
+	debugLevel := factory.NewLogger("DEBUG")
+	traceLevel := factory.NewLogger("TRACE")
+
+	disabledLogger, ok := disabled.(*logging.DefaultLeveledLogger)
+	if !ok {
+		t.Error("Missing disabled logger")
+	}
+
+	errorLogger, ok := errorLevel.(*logging.DefaultLeveledLogger)
+	if !ok {
+		t.Error("Missing error logger")
+	}
+
+	warnLogger, ok := warnLevel.(*logging.DefaultLeveledLogger)
+	if !ok {
+		t.Error("Missing warn logger")
+	}
+
+	infoLogger, ok := infoLevel.(*logging.DefaultLeveledLogger)
+	if !ok {
+		t.Error("Missing info logger")
+	}
+
+	debugLogger, ok := debugLevel.(*logging.DefaultLeveledLogger)
+	if !ok {
+		t.Error("Missing debug logger")
+	}
+
+	traceLogger, ok := traceLevel.(*logging.DefaultLeveledLogger)
+	if !ok {
+		t.Error("Missing trace logger")
+	}
+
+	testNoDebugLevel(t, disabledLogger)
+	testNoDebugLevel(t, errorLogger)
+	testNoDebugLevel(t, warnLogger)
+	testNoDebugLevel(t, infoLogger)
+	testNoDebugLevel(t, debugLogger)
+	testNoDebugLevel(t, traceLogger)
+}
+
+func TestNewDefaultLoggerFactoryLogAll(t *testing.T) {
+	t.Setenv("PION_LOG_ERROR", "all")
+	t.Setenv("PION_LOG_WARN", "all")
+	t.Setenv("PION_LOG_INFO", "all")
+	t.Setenv("PION_LOG_DEBUG", "all")
+	t.Setenv("PION_LOG_TRACE", "all")
+
+	factory := logging.NewDefaultLoggerFactory()
+
+	testAPI, ok := factory.NewLogger("test").(*logging.DefaultLeveledLogger)
+	if !ok {
+		t.Error("Invalid logger factory type")
+	}
+
+	testAllLevels(t, testAPI)
+}
+
+func TestNewDefaultLoggerFactorySpecifcScopes(t *testing.T) {
+	t.Setenv("PION_LOG_DEBUG", "feature,rtp-logger")
+
+	factory := logging.NewDefaultLoggerFactory()
+
+	feature, ok := factory.NewLogger("feature").(*logging.DefaultLeveledLogger)
+	if !ok {
+		t.Error("Invalid logger factory type")
+	}
+
+	rtp, ok := factory.NewLogger("rtp-logger").(*logging.DefaultLeveledLogger)
+	if !ok {
+		t.Error("Invalid logger factory type")
+	}
+
+	noScope, ok := factory.NewLogger("no-scope").(*logging.DefaultLeveledLogger)
+	if !ok {
+		t.Error("Invalid logger factory type")
+	}
+
+	testDebugLevel(t, feature)
+	testDebugLevel(t, rtp)
+	testNoDebugLevel(t, noScope)
+}
+
 func TestSetLevel(t *testing.T) {
 	logger := logging.
 		NewDefaultLeveledLoggerForScope("testSetLevel", logging.LogLevelWarn, os.Stderr)
@@ -123,3 +257,38 @@ func TestSetLevel(t *testing.T) {
 	logger.SetLevel(logging.LogLevelDebug)
 	testDebugLevel(t, logger)
 }
+
+func TestLogLevel(t *testing.T) {
+	logLevel := logging.LogLevelDisabled
+
+	logLevel.Set(logging.LogLevelError)
+	if logLevel.Get() != logging.LogLevelError {
+		t.Error("LogLevel was not set to LogLevelError")
+	}
+}
+
+func TestLogLevelString(t *testing.T) {
+	expected := map[logging.LogLevel]string{
+		logging.LogLevelDisabled: "Disabled",
+		logging.LogLevelError:    "Error",
+		logging.LogLevelWarn:     "Warn",
+		logging.LogLevelInfo:     "Info",
+		logging.LogLevelDebug:    "Debug",
+		logging.LogLevelTrace:    "Trace",
+		logging.LogLevel(999):    "UNKNOWN",
+	}
+
+	for level, expectedStr := range expected {
+		if level.String() != expectedStr {
+			t.Errorf("Expected %q, got %q", expectedStr, level.String())
+		}
+	}
+}
+
+func TestNewDefaultLoggerStderr(t *testing.T) {
+	logger := logging.NewDefaultLeveledLoggerForScope("test", logging.LogLevelWarn, nil)
+
+	testNoDebugLevel(t, logger)
+	testWarnLevel(t, logger)
+	testErrorLevel(t, logger)
+}