增加单一源保护全局策略

apps/api/internal/runner/retry_decision_test.go

@@ -37,6 +37,40 @@ func TestFailoverBudgetDefaults(t *testing.T) {
 	}
 }
 
+func TestSingleSourceProtectionDefaultsOn(t *testing.T) {
+	runnerPolicy := store.RunnerPolicy{Status: "active"}
+
+	if !singleSourceProtectionActive([]store.RuntimeModelCandidate{{PlatformID: "only-source"}}, 99, runnerPolicy) {
+		t.Fatal("single source protection should default to enabled")
+	}
+}
+
+func TestSingleSourceProtectionCanBeDisabled(t *testing.T) {
+	runnerPolicy := store.RunnerPolicy{
+		Status:             "active",
+		SingleSourcePolicy: map[string]any{"enabled": false},
+	}
+
+	if singleSourceProtectionActive([]store.RuntimeModelCandidate{{PlatformID: "only-source"}}, 99, runnerPolicy) {
+		t.Fatal("single source protection should respect the global toggle")
+	}
+}
+
+func TestSingleSourceProtectionUsesEffectivePlatformBudget(t *testing.T) {
+	candidates := []store.RuntimeModelCandidate{
+		{PlatformID: "first-source"},
+		{PlatformID: "second-source"},
+	}
+	runnerPolicy := store.RunnerPolicy{Status: "active"}
+
+	if !singleSourceProtectionActive(candidates, 1, runnerPolicy) {
+		t.Fatal("maxPlatforms=1 should make this execution a single-source run")
+	}
+	if singleSourceProtectionActive(candidates, 2, runnerPolicy) {
+		t.Fatal("multiple effective sources should allow disable and cooldown actions")
+	}
+}
+
 func TestFailoverTimeBudgetExceeded(t *testing.T) {
 	if !failoverTimeBudgetExceeded(time.Now().Add(-601*time.Second), 10*time.Minute) {
 		t.Fatal("failover time budget should stop retries after the configured duration")