chore: global sync per minute safety limit (#2765)

packages/snjs/lib/Services/Sync/SyncFrequencyGuard.spec.ts

@@ -0,0 +1,38 @@
+import { SyncFrequencyGuard } from './SyncFrequencyGuard'
+
+describe('SyncFrequencyGuard', () => {
+  const createUseCase = () => new SyncFrequencyGuard(3)
+
+  it('should return false when sync calls threshold is not reached', () => {
+    const useCase = createUseCase()
+
+    expect(useCase.isSyncCallsThresholdReachedThisMinute()).toBe(false)
+  })
+
+  it('should return true when sync calls threshold is reached', () => {
+    const useCase = createUseCase()
+
+    useCase.incrementCallsPerMinute()
+    useCase.incrementCallsPerMinute()
+    useCase.incrementCallsPerMinute()
+
+    expect(useCase.isSyncCallsThresholdReachedThisMinute()).toBe(true)
+  })
+
+  it('should return false when sync calls threshold is reached but a new minute has started', () => {
+    const spyOnGetCallsPerMinuteKey = jest.spyOn(SyncFrequencyGuard.prototype as any, 'getCallsPerMinuteKey')
+    spyOnGetCallsPerMinuteKey.mockReturnValueOnce('2020-1-1T1:1')
+
+    const useCase = createUseCase()
+
+    useCase.incrementCallsPerMinute()
+    useCase.incrementCallsPerMinute()
+    useCase.incrementCallsPerMinute()
+
+    spyOnGetCallsPerMinuteKey.mockReturnValueOnce('2020-1-1T1:2')
+
+    expect(useCase.isSyncCallsThresholdReachedThisMinute()).toBe(false)
+
+    spyOnGetCallsPerMinuteKey.mockRestore()
+  })
+})