stdlib: implemented bats package for running bats script from dagger

Signed-off-by: Sam Alba <samalba@users.noreply.github.com>

stdlib/bats/bats.cue

@@ -0,0 +1,56 @@
+package bats
+
+import (
+	"strings"
+
+	"alpha.dagger.io/dagger"
+	"alpha.dagger.io/os"
+	"alpha.dagger.io/alpine"
+)
+
+#Bats: {
+	// Source containing bats files
+	source: dagger.#Artifact & dagger.#Input
+
+	// bats options
+	options: [...string]
+
+	// mount points passed to the bats container
+	mount: [string]: from: dagger.#Artifact
+
+	// environment variables
+	env: [string]: string
+
+	// socket mounts for the bats container
+	socket: [string]: dagger.#Stream
+
+	// setup commands to run only once (for installing dependencies)
+	setupCommands: [...string]
+
+	// init script to run right before bats
+	initScript: string | *""
+
+	defaultOptions: ["--print-output-on-failure", "--show-output-of-passing-tests"]
+
+	ctr: os.#Container & {
+		image: alpine.#Image & {
+			package: curl: true
+			package: bash: "~=5.1"
+			package: jq:   "~=1.6"
+			package: npm:  true
+			package: git:  true
+		}
+		shell: path: "/bin/bash"
+		setup:   ["npm install -g bats"] + setupCommands
+		command: #"""
+            \#(initScript)
+            bats \#(strings.Join(defaultOptions, " ")) \#(strings.Join(options, " ")) ../src
+            """#
+
+		dir:     "/app"
+		"mount": mount
+		"mount": "/src": from: source
+		"env":    env
+		"socket": socket
+	}
+}

stdlib/bats/tests/bats.cue

@@ -1,7 +1,7 @@
 package main
 
 import (
-    "alpha.dagger.io/bats"
+	"alpha.dagger.io/bats"
 )
 
 TestBats: bats.#Bats