Validate log level and improve test coverage

Added validation to ensure log levels are within valid bounds in `SetLogLevel`. Simplified prefix mapping logic by removing the fallback to INFO level. Expanded test coverage with new test cases for plain text and JSON log outputs.

log.go

@@ -111,6 +111,10 @@ func InitStoneLog(level StoneLevel, jsonMode, disableSuffixes bool) {
 
 // SetLogLevel sets the current log level to the specified StoneLevel.
 func SetLogLevel(level StoneLevel) {
+	if level < TRACE || level > PANIC {
+		return
+	}
+
 	currentLogLevel = level
 	Observation("Log level set to %v", level)
 }
@@ -221,11 +225,7 @@ func getRandomPrefix(level StoneLevel) string {
 		FATAL: stonePanicPrefixes,
 	}
 
-	// Default to INFO prefixes if level is not in the map
+	prefixes := prefixMap[level]
-	prefixes, exists := prefixMap[level]
-	if !exists {
-		prefixes = stoneInfoPrefixes
-	}
 
 	// Select and return a random prefix
 	return prefixes[rand.Intn(len(prefixes))]

log_test.go

@@ -45,3 +45,25 @@ func Test_LogLevelColor(t *testing.T) {
 		}
 	}
 }
+
+func Test_PlainTextLogs(t *testing.T) {
+	InitStoneLog(TRACE, false, false)
+	Trace("This is a trace log")
+	Debug("This is a debug log")
+	Observation("This is an observation log")
+	Hypothesis("This is a hypothesis log")
+	Failure("This is a failure log")
+
+	SetLogLevel(INFO)
+}
+
+func Test_JSONLogs(t *testing.T) {
+	InitStoneLog(TRACE, true, false)
+	Trace("This is a trace log")
+	Debug("This is a debug log")
+	Observation("This is an observation log")
+	Hypothesis("This is a hypothesis log")
+	Failure("This is a failure log")
+
+	SetLogLevel(INFO)
+}