diff --git a/packages/graphql/api/customer.test.ts b/packages/graphql/api/customer.test.ts
new file mode 100644
index 0000000..0b85a49
--- /dev/null
+++ b/packages/graphql/api/customer.test.ts
@@ -0,0 +1,110 @@
+import { beforeEach, describe, expect, it, Mock, vi } from 'vitest';
+import * as ApolloClient from '../apollo/client';
+import * as GQL from '../types';
+import { createOrUpdateUser } from './customer';
+
+vi.mock('../apollo/client', () => ({
+  getClientWithToken: vi.fn(),
+}));
+
+const mockQuery = vi.fn();
+const mockMutate = vi.fn();
+
+type ApolloResponse<TData> = {
+  data: TData;
+};
+
+describe('api/customer', () => {
+  describe('createOrUpdateUser', () => {
+    beforeEach(() => {
+      vi.clearAllMocks();
+      (ApolloClient.getClientWithToken as Mock).mockResolvedValue({
+        query: mockQuery,
+        mutate: mockMutate,
+      });
+    });
+
+    const variables: GQL.CreateUserMutationVariables = {
+      name: 'John Doe',
+      phone: '1234567890',
+      telegramId: '1234567890',
+    };
+
+    const user: GQL.CustomerProfileFragment = {
+      __typename: 'Customer',
+      documentId: '123',
+      name: 'John Doe',
+      phone: '1234567890',
+      telegramId: '1234567890',
+      role: GQL.Enum_Customer_Role.Client,
+      masters: [],
+    };
+
+    it('create new user if it does not exist', async () => {
+      mockQuery.mockResolvedValueOnce({
+        data: {
+          customers: [],
+        },
+      });
+
+      const mockCreateResponse: ApolloResponse<GQL.CreateUserMutation> = {
+        data: { createCustomer: user },
+      };
+      mockMutate.mockResolvedValueOnce(mockCreateResponse);
+
+      const result = await createOrUpdateUser(variables);
+
+      expect(mockQuery).toHaveBeenCalledWith({
+        query: GQL.GetUserByPhoneDocument,
+        variables,
+      });
+
+      expect(mockMutate).toHaveBeenCalledWith({
+        mutation: GQL.CreateUserDocument,
+        variables,
+      });
+
+      expect(mockMutate).not.toHaveBeenCalledWith({
+        mutation: GQL.UpdateCustomerProfileDocument,
+        variables,
+      });
+
+      expect(result).toEqual(mockCreateResponse);
+    });
+
+    it('update user if it exists', async () => {
+      mockQuery.mockResolvedValueOnce({
+        data: {
+          customers: [user],
+        },
+      });
+
+      const mockUpdateResponse: ApolloResponse<GQL.UpdateCustomerProfileMutation> = {
+        data: { updateCustomer: user },
+      };
+      mockMutate.mockResolvedValueOnce(mockUpdateResponse);
+
+      const result = await createOrUpdateUser(variables);
+
+      expect(mockQuery).toHaveBeenCalledWith({
+        query: GQL.GetUserByPhoneDocument,
+        variables,
+      });
+
+      expect(mockMutate).toHaveBeenCalledWith({
+        mutation: GQL.UpdateCustomerProfileDocument,
+        variables: {
+          documentId: user.documentId,
+          data: variables,
+        },
+      });
+
+      expect(mockMutate).not.toHaveBeenCalledWith({
+        mutation: GQL.CreateUserDocument,
+        variables,
+      });
+
+      expect(result).toEqual(mockUpdateResponse);
+    });
+  });
+});