cli: handle help, -h and --help, close #463 (#464)

cli/__snapshots__/cli_spec.js

@@ -1,3 +1,108 @@
+exports['cli help command shows help 1'] = `
+
+  command: bin/cypress help
+  code: 0
+  failed: false
+  killed: false
+  signal: null
+  timedOut: false
+
+  stdout:
+  -------
+  Usage: cypress [options] [command]
+
+
+  Commands:
+
+    help             Shows CLI help and exits
+    version          Prints Cypress version
+    run [options]    Runs Cypress tests from the CLI without the GUI
+    open [options]   Opens Cypress in the interactive GUI.
+    install          Installs the Cypress executable matching this package's version
+    verify           Verifies that Cypress is installed correctly and executable
+
+  Options:
+
+    -h, --help     output usage information
+    -v, --version  Prints Cypress version
+  -------
+  stderr:
+  -------
+  
+  -------
+  
+`
+
+exports['cli help command shows help for -h 1'] = `
+
+  command: bin/cypress -h
+  code: 0
+  failed: false
+  killed: false
+  signal: null
+  timedOut: false
+
+  stdout:
+  -------
+  Usage: cypress [options] [command]
+
+
+  Commands:
+
+    help             Shows CLI help and exits
+    version          Prints Cypress version
+    run [options]    Runs Cypress tests from the CLI without the GUI
+    open [options]   Opens Cypress in the interactive GUI.
+    install          Installs the Cypress executable matching this package's version
+    verify           Verifies that Cypress is installed correctly and executable
+
+  Options:
+
+    -h, --help     output usage information
+    -v, --version  Prints Cypress version
+  -------
+  stderr:
+  -------
+  
+  -------
+  
+`
+
+exports['cli help command shows help for --help 1'] = `
+
+  command: bin/cypress --help
+  code: 0
+  failed: false
+  killed: false
+  signal: null
+  timedOut: false
+
+  stdout:
+  -------
+  Usage: cypress [options] [command]
+
+
+  Commands:
+
+    help             Shows CLI help and exits
+    version          Prints Cypress version
+    run [options]    Runs Cypress tests from the CLI without the GUI
+    open [options]   Opens Cypress in the interactive GUI.
+    install          Installs the Cypress executable matching this package's version
+    verify           Verifies that Cypress is installed correctly and executable
+
+  Options:
+
+    -h, --help     output usage information
+    -v, --version  Prints Cypress version
+  -------
+  stderr:
+  -------
+  
+  -------
+  
+`
+
 exports['cli unknown command shows usage and exits 1'] = `
 
   command: bin/cypress foo
@@ -16,6 +121,7 @@ exports['cli unknown command shows usage and exits 1'] = `
 
     Commands:
 
+      help             Shows CLI help and exits
       version          Prints Cypress version
       run [options]    Runs Cypress tests from the CLI without the GUI
       open [options]   Opens Cypress in the interactive GUI.

cli/lib/cli.js

@@ -29,7 +29,7 @@ const descriptions = {
   version: 'Prints Cypress version',
 }
 
-const knownCommands = ['version', 'run', 'open', 'install', 'verify', '-v', '--version']
+const knownCommands = ['version', 'run', 'open', 'install', 'verify', '-v', '--version', 'help', '-h', '--help']
 
 const text = (description) => {
   if (!descriptions[description]) {
@@ -51,6 +51,13 @@ module.exports = {
     // in usage help docs
     program._name = 'cypress'
 
+    program
+      .command('help')
+      .description('Shows CLI help and exits')
+      .action(() => {
+        program.help()
+      })
+
     program
       .option('-v, --version', text('version'))
       .command('version')

cli/test/lib/cli_spec.js

@@ -20,6 +20,20 @@ describe('cli', function () {
     this.exec = (args) => cli.init(`node test ${args}`.split(' '))
   })
 
+  context('help command', () => {
+    it('shows help', () =>
+      execa('bin/cypress', ['help']).then(snapshot)
+    )
+
+    it('shows help for -h', () =>
+      execa('bin/cypress', ['-h']).then(snapshot)
+    )
+
+    it('shows help for --help', () =>
+      execa('bin/cypress', ['--help']).then(snapshot)
+    )
+  })
+
   context('unknown command', () => {
     it('shows usage and exits', () =>
       execa('bin/cypress', ['foo']).then(snapshot)