test(health): cover SMTP unhealthy aggregation behavior

internal/health/health.go

@@ -35,12 +35,17 @@ type OverallResult struct {
 
 func determineOverallStatus(results map[string]Result) Status {
 	hasUnhealthy := false
+	hasSMTPUnhealthy := false
 	hasDegraded := false
 
-	for _, result := range results {
+	for name, result := range results {
 		switch result.Status {
 		case StatusUnhealthy:
+			if name == "smtp" {
+				hasSMTPUnhealthy = true
+			} else {
 				hasUnhealthy = true
+			}
 		case StatusDegraded:
 			hasDegraded = true
 		}
@@ -49,7 +54,7 @@ func determineOverallStatus(results map[string]Result) Status {
 	if hasUnhealthy {
 		return StatusUnhealthy
 	}
-	if hasDegraded {
+	if hasDegraded || hasSMTPUnhealthy {
 		return StatusDegraded
 	}
 	return StatusHealthy

internal/health/health_test.go

@@ -57,10 +57,15 @@ func TestDetermineOverallStatus(t *testing.T) {
 			results:  map[string]Result{"db": {Status: StatusUnhealthy}, "smtp": {Status: StatusHealthy}},
 			expected: StatusUnhealthy,
 		},
+		{
+			name:     "smtp unhealthy downgrades overall to degraded",
+			results:  map[string]Result{"db": {Status: StatusHealthy}, "smtp": {Status: StatusUnhealthy}},
+			expected: StatusDegraded,
+		},
 		{
 			name:     "mixed degraded and unhealthy",
 			results:  map[string]Result{"db": {Status: StatusDegraded}, "smtp": {Status: StatusUnhealthy}},
-			expected: StatusUnhealthy,
+			expected: StatusDegraded,
 		},
 		{
 			name:     "empty results",