diff --git a/packages/@sanity/migrate/src/runner/__tests__/normalizeMigrationDefinition.test.ts b/packages/@sanity/migrate/src/runner/__tests__/normalizeMigrationDefinition.test.ts
new file mode 100644
index 00000000000..f38663219f0
--- /dev/null
+++ b/packages/@sanity/migrate/src/runner/__tests__/normalizeMigrationDefinition.test.ts
@@ -0,0 +1,103 @@
+import {
+  createAsyncIterableMutation,
+  normalizeMigrateDefinition,
+} from '../normalizeMigrateDefinition'
+import {Migration, NodeMigration} from '../../types'
+import {createIfNotExists} from '../../mutations'
+
+const mockAsyncIterableIterator = () => {
+  const data = [{_id: 'mockId', _type: 'mockDocumentType'}]
+  let index = 0
+
+  return {
+    next: jest.fn().mockImplementation(() => {
+      if (index < data.length) {
+        return Promise.resolve({value: data[index++], done: false})
+      }
+      return Promise.resolve({value: undefined, done: true})
+    }),
+    [Symbol.asyncIterator]: jest.fn().mockImplementation(function (this: unknown) {
+      return this
+    }),
+  }
+}
+
+describe('#normalizeMigrateDefinition', () => {
+  it('should return the migrate is a function', async () => {
+    const mockMigration: Migration = {
+      title: 'mockMigration',
+      documentTypes: ['mockDocumentType'],
+      async *migrate() {
+        yield createIfNotExists({_type: 'mockDocumentType', _id: 'mockId'})
+      },
+    }
+
+    const result = normalizeMigrateDefinition(mockMigration)
+
+    const res = []
+    for await (const item of result(jest.fn(), {} as any)) {
+      res.push(item)
+    }
+
+    expect(res.flat()).toEqual([createIfNotExists({_type: 'mockDocumentType', _id: 'mockId'})])
+  })
+
+  it('should return a new mutations if migrate is not a function', async () => {
+    const mockMigration: Migration = {
+      title: 'mockMigration',
+      documentTypes: ['mockDocumentType'],
+      migrate: {
+        document() {
+          return createIfNotExists({_type: 'mockDocumentType', _id: 'mockId'})
+        },
+      },
+    }
+
+    const result = normalizeMigrateDefinition(mockMigration)
+    const res = []
+
+    for await (const item of result(mockAsyncIterableIterator, {} as any)) {
+      res.push(item)
+    }
+
+    expect(res.flat()).toEqual([createIfNotExists({_type: 'mockDocumentType', _id: 'mockId'})])
+  })
+
+  it('should not return undefined if migrate is returning undefined', async () => {
+    const mockMigration: Migration = {
+      title: 'mockMigration',
+      documentTypes: ['mockDocumentType'],
+      migrate: {
+        document() {
+          return undefined
+        },
+      },
+    }
+
+    const result = normalizeMigrateDefinition(mockMigration)
+    const res = []
+
+    for await (const item of result(mockAsyncIterableIterator, {} as any)) {
+      res.push(item)
+    }
+
+    expect(res.flat()).toEqual([])
+  })
+})
+
+describe('#createAsyncIterableMutation', () => {
+  it('should return an async iterable', async () => {
+    const mockMigration: NodeMigration = {
+      document: jest.fn(),
+    }
+
+    const iterable = createAsyncIterableMutation(mockMigration, {documentTypes: ['foo']})
+
+    expect(typeof iterable).toBe('function')
+
+    const iterator = iterable(mockAsyncIterableIterator() as any, {} as any)
+    expect(typeof iterator.next).toBe('function')
+    expect(typeof iterator.return).toBe('function')
+    expect(typeof iterator.throw).toBe('function')
+  })
+})