diff --git a/tests/domain/runtime-project-scheduler.test.ts b/tests/domain/runtime-project-scheduler.test.ts
new file mode 100644
index 00000000..26ffeee2
--- /dev/null
+++ b/tests/domain/runtime-project-scheduler.test.ts
@@ -0,0 +1,156 @@
+import { describe, expect, it } from "vitest";
+
+import {
+  createActorControlTargetRef,
+  createEmptyRuntimeResolvedControlState,
+  createSetActorPresenceControlEffect
+} from "../../src/controls/control-surface";
+import {
+  createEmptyProjectScheduler,
+  createProjectScheduleRoutine,
+  createProjectScheduleSelectedDaysSelection
+} from "../../src/scheduler/project-scheduler";
+import {
+  applyRuntimeProjectScheduleToControlState,
+  resolveRuntimeProjectScheduleState
+} from "../../src/runtime-three/runtime-project-scheduler";
+
+describe("runtime project scheduler", () => {
+  it("resolves cross-midnight actor routines and keeps unscheduled actors implicitly active", () => {
+    const actorTarget = createActorControlTargetRef("actor-night-watch");
+    const scheduler = createEmptyProjectScheduler();
+    scheduler.routines["routine-night-watch"] = createProjectScheduleRoutine({
+      id: "routine-night-watch",
+      title: "Night Watch",
+      target: actorTarget,
+      days: createProjectScheduleSelectedDaysSelection(["monday"]),
+      startHour: 22,
+      endHour: 2,
+      effect: createSetActorPresenceControlEffect({
+        target: actorTarget,
+        active: true
+      })
+    });
+
+    expect(
+      resolveRuntimeProjectScheduleState({
+        scheduler,
+        actorIds: ["actor-night-watch", "actor-always-on"],
+        dayNumber: 1,
+        timeOfDayHours: 23
+      }).actors
+    ).toEqual(
+      expect.arrayContaining([
+        expect.objectContaining({
+          actorId: "actor-night-watch",
+          hasRules: true,
+          active: true,
+          activeRoutineId: "routine-night-watch",
+          activeRoutineTitle: "Night Watch"
+        }),
+        expect.objectContaining({
+          actorId: "actor-always-on",
+          hasRules: false,
+          active: true,
+          activeRoutineId: null,
+          activeRoutineTitle: null
+        })
+      ])
+    );
+
+    expect(
+      resolveRuntimeProjectScheduleState({
+        scheduler,
+        actorIds: ["actor-night-watch"],
+        dayNumber: 2,
+        timeOfDayHours: 1.5
+      }).actors[0]
+    ).toEqual(
+      expect.objectContaining({
+        actorId: "actor-night-watch",
+        active: true,
+        activeRoutineTitle: "Night Watch"
+      })
+    );
+
+    expect(
+      resolveRuntimeProjectScheduleState({
+        scheduler,
+        actorIds: ["actor-night-watch"],
+        dayNumber: 2,
+        timeOfDayHours: 3
+      }).actors[0]
+    ).toEqual(
+      expect.objectContaining({
+        actorId: "actor-night-watch",
+        hasRules: true,
+        active: false,
+        activeRoutineId: null,
+        activeRoutineTitle: null
+      })
+    );
+  });
+
+  it("prefers the highest-priority active routine and writes actor presence into resolved control state", () => {
+    const actorTarget = createActorControlTargetRef("actor-market-vendor");
+    const scheduler = createEmptyProjectScheduler();
+    scheduler.routines["routine-open"] = createProjectScheduleRoutine({
+      id: "routine-open",
+      title: "Open Stall",
+      target: actorTarget,
+      startHour: 9,
+      endHour: 18,
+      priority: 0,
+      effect: createSetActorPresenceControlEffect({
+        target: actorTarget,
+        active: true
+      })
+    });
+    scheduler.routines["routine-break"] = createProjectScheduleRoutine({
+      id: "routine-break",
+      title: "Lunch Break",
+      target: actorTarget,
+      startHour: 12,
+      endHour: 13.5,
+      priority: 5,
+      effect: createSetActorPresenceControlEffect({
+        target: actorTarget,
+        active: false
+      })
+    });
+
+    const resolvedSchedule = resolveRuntimeProjectScheduleState({
+      scheduler,
+      actorIds: ["actor-market-vendor"],
+      dayNumber: 1,
+      timeOfDayHours: 12.25
+    });
+    const resolvedControl = applyRuntimeProjectScheduleToControlState(
+      createEmptyRuntimeResolvedControlState(),
+      resolvedSchedule
+    );
+
+    expect(resolvedSchedule.actors[0]).toEqual(
+      expect.objectContaining({
+        actorId: "actor-market-vendor",
+        active: false,
+        activeRoutineId: "routine-break",
+        activeRoutineTitle: "Lunch Break"
+      })
+    );
+    expect(resolvedControl.discrete).toEqual([
+      expect.objectContaining({
+        type: "actorPresence",
+        target: {
+          kind: "actor",
+          actorId: "actor-market-vendor"
+        },
+        value: false,
+        source: {
+          kind: "scheduler",
+          scheduleId: "routine-break"
+        }
+      })
+    ]);
+  });
+});