Add File Commands (#571)

* Add File Commands

* pr updates w/ feedback

* run format

* fix lint/format

* slight update with an example in the docs

* pr feedback

packages/core/__tests__/core.test.ts

@@ -1,3 +1,4 @@
+import * as fs from 'fs'
 import * as os from 'os'
 import * as path from 'path'
 import * as core from '../src/core'
@@ -20,27 +21,34 @@ const testEnvVars = {
   INPUT_MULTIPLE_SPACES_VARIABLE: 'I have multiple spaces',
 
   // Save inputs
-  STATE_TEST_1: 'state_val'
+  STATE_TEST_1: 'state_val',
+
+  // File Commands
+  GITHUB_PATH: '',
+  GITHUB_ENV: ''
 }
 
 describe('@actions/core', () => {
-  beforeEach(() => {
-    for (const key in testEnvVars)
-      process.env[key] = testEnvVars[key as keyof typeof testEnvVars]
+  beforeAll(() => {
+    const filePath = path.join(__dirname, `test`)
+    if (!fs.existsSync(filePath)) {
+      fs.mkdirSync(filePath)
+    }
+  })
 
+  beforeEach(() => {
+    for (const key in testEnvVars) {
+      process.env[key] = testEnvVars[key as keyof typeof testEnvVars]
+    }
     process.stdout.write = jest.fn()
   })
 
-  afterEach(() => {
-    for (const key in testEnvVars) Reflect.deleteProperty(testEnvVars, key)
-  })
-
-  it('exportVariable produces the correct command and sets the env', () => {
+  it('legacy exportVariable produces the correct command and sets the env', () => {
     core.exportVariable('my var', 'var val')
     assertWriteCalls([`::set-env name=my var::var val${os.EOL}`])
   })
 
-  it('exportVariable escapes variable names', () => {
+  it('legacy exportVariable escapes variable names', () => {
     core.exportVariable('special char var \r\n,:', 'special val')
     expect(process.env['special char var \r\n,:']).toBe('special val')
     assertWriteCalls([
@@ -48,28 +56,68 @@ describe('@actions/core', () => {
     ])
   })
 
-  it('exportVariable escapes variable values', () => {
+  it('legacy exportVariable escapes variable values', () => {
     core.exportVariable('my var2', 'var val\r\n')
     expect(process.env['my var2']).toBe('var val\r\n')
     assertWriteCalls([`::set-env name=my var2::var val%0D%0A${os.EOL}`])
   })
 
-  it('exportVariable handles boolean inputs', () => {
+  it('legacy exportVariable handles boolean inputs', () => {
     core.exportVariable('my var', true)
     assertWriteCalls([`::set-env name=my var::true${os.EOL}`])
   })
 
-  it('exportVariable handles number inputs', () => {
+  it('legacy exportVariable handles number inputs', () => {
     core.exportVariable('my var', 5)
     assertWriteCalls([`::set-env name=my var::5${os.EOL}`])
   })
 
+  it('exportVariable produces the correct command and sets the env', () => {
+    const command = 'ENV'
+    createFileCommandFile(command)
+    core.exportVariable('my var', 'var val')
+    verifyFileCommand(
+      command,
+      `my var<<_GitHubActionsFileCommandDelimeter_${os.EOL}var val${os.EOL}_GitHubActionsFileCommandDelimeter_${os.EOL}`
+    )
+  })
+
+  it('exportVariable handles boolean inputs', () => {
+    const command = 'ENV'
+    createFileCommandFile(command)
+    core.exportVariable('my var', true)
+    verifyFileCommand(
+      command,
+      `my var<<_GitHubActionsFileCommandDelimeter_${os.EOL}true${os.EOL}_GitHubActionsFileCommandDelimeter_${os.EOL}`
+    )
+  })
+
+  it('exportVariable handles number inputs', () => {
+    const command = 'ENV'
+    createFileCommandFile(command)
+    core.exportVariable('my var', 5)
+    verifyFileCommand(
+      command,
+      `my var<<_GitHubActionsFileCommandDelimeter_${os.EOL}5${os.EOL}_GitHubActionsFileCommandDelimeter_${os.EOL}`
+    )
+  })
+
   it('setSecret produces the correct command', () => {
     core.setSecret('secret val')
     assertWriteCalls([`::add-mask::secret val${os.EOL}`])
   })
 
   it('prependPath produces the correct commands and sets the env', () => {
+    const command = 'PATH'
+    createFileCommandFile(command)
+    core.addPath('myPath')
+    expect(process.env['PATH']).toBe(
+      `myPath${path.delimiter}path1${path.delimiter}path2`
+    )
+    verifyFileCommand(command, `myPath${os.EOL}`)
+  })
+
+  it('legacy prependPath produces the correct commands and sets the env', () => {
     core.addPath('myPath')
     expect(process.env['PATH']).toBe(
       `myPath${path.delimiter}path1${path.delimiter}path2`
@@ -259,3 +307,21 @@ function assertWriteCalls(calls: string[]): void {
     expect(process.stdout.write).toHaveBeenNthCalledWith(i + 1, calls[i])
   }
 }
+
+function createFileCommandFile(command: string): void {
+  const filePath = path.join(__dirname, `test/${command}`)
+  process.env[`GITHUB_${command}`] = filePath
+  fs.appendFileSync(filePath, '', {
+    encoding: 'utf8'
+  })
+}
+
+function verifyFileCommand(command: string, expectedContents: string): void {
+  const filePath = path.join(__dirname, `test/${command}`)
+  const contents = fs.readFileSync(filePath, 'utf8')
+  try {
+    expect(contents).toEqual(expectedContents)
+  } finally {
+    fs.unlinkSync(filePath)
+  }
+}