diff --git a/__tests__/strategies/seed.test.ts b/__tests__/strategies/seed.test.ts
new file mode 100644
index 0000000..6964772
--- /dev/null
+++ b/__tests__/strategies/seed.test.ts
@@ -0,0 +1,185 @@
+import {
+  AbstractScheduler,
+  Card,
+  createEmptyCard,
+  DefaultInitSeedStrategy,
+  fsrs,
+  GenSeedStrategyWithCardId,
+  Rating,
+  StrategyMode,
+} from '../../src/fsrs'
+
+interface ICard extends Card {
+  card_id: number
+}
+
+describe('seed strategy', () => {
+  it('default seed strategy', () => {
+    const seedStrategy = DefaultInitSeedStrategy
+    const f = fsrs().useStrategy(StrategyMode.SEED, seedStrategy)
+    const now = Date.UTC(2022, 11, 29, 12, 30, 0, 0)
+
+    const card = createEmptyCard<ICard>(now, (card: Card) => {
+      Object.assign(card, { card_id: 555 })
+      return card as ICard
+    })
+
+    const record = f.repeat(card, now)
+    const scheduler = new f['Scheduler'](card, now, f, {
+      seed: seedStrategy,
+    }) as AbstractScheduler
+
+    const seed = seedStrategy.bind(scheduler)()
+    console.debug('seed', seed)
+
+    expect(f['_seed']).toBe(seed)
+  })
+})
+
+describe('seed strategy with card ID', () => {
+  it('use seedStrategy', () => {
+    const seedStrategy = GenSeedStrategyWithCardId('card_id')
+    const f = fsrs().useStrategy(StrategyMode.SEED, seedStrategy)
+
+    expect(f['strategyHandler'].get(StrategyMode.SEED)).toBe(seedStrategy)
+
+    f.clearStrategy()
+    expect(f['strategyHandler'].get(StrategyMode.SEED)).toBeUndefined()
+  })
+  it('clear seedStrategy', () => {
+    const seedStrategy = GenSeedStrategyWithCardId('card_id')
+    const f = fsrs().useStrategy(StrategyMode.SEED, seedStrategy)
+    const now = Date.UTC(2022, 11, 29, 12, 30, 0, 0)
+
+    const card = createEmptyCard<ICard>(now, (card: Card) => {
+      Object.assign(card, { card_id: 555 })
+      return card as ICard
+    })
+
+    f.repeat(card, now)
+    let scheduler = new f['Scheduler'](card, now, f, {
+      seed: seedStrategy,
+    }) as AbstractScheduler
+
+    const seed_with_card_id = seedStrategy.bind(scheduler)()
+    console.debug('seed with card_id=555', seed_with_card_id)
+
+    f.clearStrategy(StrategyMode.SEED)
+
+    f.repeat(card, now)
+    scheduler = new f['Scheduler'](card, now, f, {
+      seed: DefaultInitSeedStrategy,
+    }) as AbstractScheduler
+    const basic_seed = DefaultInitSeedStrategy.bind(scheduler)()
+    console.debug('basic_seed with card_id=555', basic_seed)
+
+    expect(f['_seed']).toBe(basic_seed)
+
+    expect(seed_with_card_id).not.toBe(basic_seed)
+  })
+
+  it('exist card_id', () => {
+    const seedStrategy = GenSeedStrategyWithCardId('card_id')
+    const f = fsrs().useStrategy(StrategyMode.SEED, seedStrategy)
+    const now = Date.UTC(2022, 11, 29, 12, 30, 0, 0)
+
+    const card = createEmptyCard<ICard>(now, (card: Card) => {
+      Object.assign(card, { card_id: 555 })
+      return card as ICard
+    })
+
+    const record = f.repeat(card, now)
+    const scheduler = new f['Scheduler'](card, now, f, {
+      seed: seedStrategy,
+    }) as AbstractScheduler
+
+    const seed = seedStrategy.bind(scheduler)()
+    console.debug('seed with card_id=555', seed)
+
+    expect(f['_seed']).toBe(seed)
+  })
+
+  it('not exist card_id', () => {
+    const seedStrategy = GenSeedStrategyWithCardId('card_id')
+    const f = fsrs().useStrategy(StrategyMode.SEED, seedStrategy)
+    const now = Date.UTC(2022, 11, 29, 12, 30, 0, 0)
+
+    const card = createEmptyCard<ICard>(now)
+
+    const record = f.repeat(card, now)
+    const scheduler = new f['Scheduler'](card, now, f, {
+      seed: seedStrategy,
+    }) as AbstractScheduler
+
+    const seed = seedStrategy.bind(scheduler)()
+    console.debug('seed with card_id=undefined(default)', seed)
+
+    expect(f['_seed']).toBe(seed)
+  })
+
+  it('card_id = -1', () => {
+    const seedStrategy = GenSeedStrategyWithCardId('card_id')
+    const f = fsrs().useStrategy(StrategyMode.SEED, seedStrategy)
+    const now = Date.UTC(2022, 11, 29, 12, 30, 0, 0)
+
+    const card = createEmptyCard<ICard>(now, (card: Card) => {
+      Object.assign(card, { card_id: -1 })
+      return card as ICard
+    })
+
+    const record = f.repeat(card, now)
+    const scheduler = new f['Scheduler'](card, now, f, {
+      seed: seedStrategy,
+    }) as AbstractScheduler
+
+    const seed = seedStrategy.bind(scheduler)()
+    console.debug('with card_id=-1', seed)
+
+    expect(f['_seed']).toBe(seed)
+    expect(f['_seed']).toBe('0')
+  })
+
+  it('card_id is undefined', () => {
+    const seedStrategy = GenSeedStrategyWithCardId('card_id')
+    const f = fsrs().useStrategy(StrategyMode.SEED, seedStrategy)
+    const now = Date.UTC(2022, 11, 29, 12, 30, 0, 0)
+
+    const card = createEmptyCard<ICard>(now, (card: Card) => {
+      Object.assign(card, { card_id: undefined })
+      return card as ICard
+    })
+
+    const item = f.next(card, now, Rating.Good)
+    const scheduler = new f['Scheduler'](card, now, f, {
+      seed: seedStrategy,
+    }) as AbstractScheduler
+
+    const seed = seedStrategy.bind(scheduler)()
+    console.debug('seed with card_id=undefined', seed)
+
+    expect(f['_seed']).toBe(seed)
+    expect(f['_seed']).toBe(`${item.card.reps}`)
+  })
+
+  it('card_id is null', () => {
+    const seedStrategy = GenSeedStrategyWithCardId('card_id')
+    const f = fsrs().useStrategy(StrategyMode.SEED, seedStrategy)
+    const now = Date.UTC(2022, 11, 29, 12, 30, 0, 0)
+
+    const card = createEmptyCard<ICard>(now, (card: Card) => {
+      Object.assign(card, { card_id: null })
+      return card as ICard
+    })
+
+    const item = f.next(card, now, Rating.Good)
+    const scheduler = new f['Scheduler'](card, now, f, {
+      seed: seedStrategy,
+    }) as AbstractScheduler
+
+    const seed = seedStrategy.bind(scheduler)()
+    console.debug('seed with card_id=null', seed)
+
+    expect(f['_seed']).toBe(seed)
+    expect(f['_seed']).toBe(`${item.card.reps}`)
+  })
+})