feat: implement theme get service tests

src/services/theme/get.test.ts

@@ -0,0 +1,45 @@
+import { beforeEach, describe, expect, test, vi } from 'vitest'
+import { fetchStoreThemes } from "@shopify/theme/dist/cli/utilities/theme-selector/fetch.js";
+import { get } from './get.js';
+import { Theme } from '@shopify/cli-kit/node/themes/types';
+
+vi.mock("@shopify/theme/dist/cli/utilities/theme-selector/fetch.js")
+
+describe('get', () => {
+  const adminSession = { token: 'ABC', storeFqdn: 'example.myshopify.com' }
+
+  function theme(id: number, role: string) {
+    return { id, role, name: `theme (${id})` } as Theme
+  }
+
+  describe("when theme is found", () => {
+    test('returns an array with the theme', async () => {
+      // Given
+      const expectedTheme = theme(1, 'unpublished')
+      const anotherTheme = theme(2, 'unpublished')
+      const themes = [expectedTheme, anotherTheme]
+      vi.mocked(fetchStoreThemes).mockResolvedValue(themes)
+
+      // When
+      const actualThemes = await get(adminSession, '1')
+
+      // Then
+      expect(actualThemes).toEqual([expectedTheme])
+    })
+  })
+  describe("when theme is not found", async () => {
+    test('throws error', () => {
+      // Given
+      const expectedTheme = theme(1, 'unpublished')
+      const anotherTheme = theme(2, 'unpublished')
+      const themes = [expectedTheme, anotherTheme]
+      vi.mocked(fetchStoreThemes).mockResolvedValue(themes)
+
+      // When
+      const errorFunc = async () => await get(adminSession, '3')
+
+      // Then
+      expect(errorFunc).toThrowError
+    })
+  })
+})