diff --git a/tests/array.spec.ts b/tests/array.spec.ts
index 7c54bc6..66803df 100644
--- a/tests/array.spec.ts
+++ b/tests/array.spec.ts
@@ -37,8 +37,12 @@ it('normalizeToArray', () => {
 
 it('removeItem', () => {
   const arr = [1, 2, 3, 4]
-  removeItem(arr, 2)
+  const removed = removeItem(arr, 2)
   expect(arr).toEqual([1, 3, 4])
+  expect(removed).toEqual([2])
+
+  expect(removeItem([], undefined)).toEqual(undefined)
+  expect(removeItem([1], 2)).toEqual(undefined)
 })
 
 it('toggleItem', () => {
@@ -72,11 +76,17 @@ describe('find', () => {
     expect(index).toBe(4)
   })
 
-  it('not found', () => {
+  it('not found from start', () => {
     const [item, index] = find([1, 2, 3, 4, 3], (item) => item === 5)
     expect(item).toBe(null)
     expect(index).toBe(-1)
   })
+
+  it('not found from end', () => {
+    const [item, index] = find([1, 2, 3, 4, 3], (item) => item === 5, 'end')
+    expect(item).toBe(null)
+    expect(index).toBe(-1)
+  })
 })
 
 it('at', () => {
diff --git a/tests/function.spec.ts b/tests/function.spec.ts
index 8008d6a..3acced9 100644
--- a/tests/function.spec.ts
+++ b/tests/function.spec.ts
@@ -3,6 +3,21 @@ import { debounce, throttle, call, once } from '../src'
 
 describe('Utility Functions', () => {
   describe('debounce', () => {
+    it('should call the function with the default delay', async () => {
+      const fn = vi.fn()
+      const debouncedFn = debounce(fn)
+
+      debouncedFn()
+      debouncedFn()
+      debouncedFn()
+
+      await new Promise((resolve) => {
+        setTimeout(resolve, 250)
+      })
+
+      expect(fn).toHaveBeenCalledTimes(1)
+    })
+
     it('should call the function after the specified delay', async () => {
       const fn = vi.fn()
       const debouncedFn = debounce(fn, 100)
@@ -34,6 +49,24 @@ describe('Utility Functions', () => {
   })
 
   describe('throttle', () => {
+    it('should call the function immediately and then at default intervals', async () => {
+      const fn = vi.fn()
+      const throttledFn = throttle(fn)
+
+      throttledFn()
+      throttledFn()
+      await new Promise((resolve) => {
+        setTimeout(resolve, 50)
+      })
+      throttledFn()
+      await new Promise((resolve) => {
+        setTimeout(resolve, 200)
+      })
+      throttledFn()
+
+      expect(fn).toHaveBeenCalledTimes(2)
+    })
+
     it('should call the function immediately and then at specified intervals', async () => {
       const fn = vi.fn()
       const throttledFn = throttle(fn, 100)
diff --git a/vitest.config.ts b/vitest.config.ts
index 207cc7b..4520702 100644
--- a/vitest.config.ts
+++ b/vitest.config.ts
@@ -6,6 +6,7 @@ export default defineConfig({
     coverage: {
       provider: 'istanbul',
       include: ['src/**/*.ts'],
+      exclude: ['src/function/NOOP.ts'],
     },
   },
 })