Add test for stdin util

test/utils/stdin.ts

@@ -0,0 +1,81 @@
+import { Readable } from 'node:stream'
+import * as cli from '../../src/cli'
+import { getStdin } from '../../src/utils/stdin'
+
+jest.unmock('../../src/utils/stdin')
+
+afterEach(() => jest.restoreAllMocks())
+
+const createMockedStream = (data: string, delay = 0) => {
+  const { length } = data
+
+  let cursor = 0
+
+  return new Readable({
+    read(size) {
+      setTimeout(() => {
+        const end = cursor + size
+
+        this.push(data.slice(cursor, end))
+        if (length < end) this.push(null)
+
+        cursor = end
+      }, delay)
+    },
+  })
+}
+
+const createMockedStdinStream = (
+  data: string,
+  { delay = 0, isTTY = false }: { delay?: number; isTTY?: boolean } = {}
+) =>
+  Object.assign(
+    createMockedStream(data, delay) as unknown as NodeJS.ReadStream,
+    { fd: 0 as const, isTTY }
+  )
+
+describe('getStdin()', () => {
+  it('always returns empty buffer if stdin is TTY', async () => {
+    jest
+      .spyOn(process, 'stdin', 'get')
+      .mockImplementation(() =>
+        createMockedStdinStream('foobar', { isTTY: true })
+      )
+
+    const buf = await getStdin()
+    expect(buf).toBeInstanceOf(Buffer)
+    expect(buf).toHaveLength(0)
+    expect(buf.toString()).toBe('')
+  })
+
+  it('reads buffer from stdin', async () => {
+    jest
+      .spyOn(process, 'stdin', 'get')
+      .mockImplementation(() => createMockedStdinStream('foobar'))
+
+    const buf = await getStdin()
+    expect(buf).toBeInstanceOf(Buffer)
+    expect(buf).toHaveLength(6)
+    expect(buf.toString()).toBe('foobar')
+  })
+
+  it('shows info message 3 seconds after reading stream', async () => {
+    jest
+      .spyOn(process, 'stdin', 'get')
+      .mockImplementation(() =>
+        createMockedStdinStream('foobar', { delay: 3210 })
+      )
+
+    jest.spyOn(cli, 'info').mockImplementation()
+
+    const buf = await getStdin()
+    expect(buf).toBeInstanceOf(Buffer)
+    expect(buf).toHaveLength(6)
+    expect(buf.toString()).toBe('foobar')
+
+    expect(cli.info).toHaveBeenCalledTimes(1)
+    expect(cli.info).toHaveBeenCalledWith(
+      expect.stringContaining('Currently waiting data from stdin stream')
+    )
+  }, 7000)
+})