basic tests for alpine go and yarn

Signed-off-by: Andrea Luzzardi <aluzzardi@gmail.com>

tests/stdlib/yarn/testdata/package.json

@@ -0,0 +1,11 @@
+{
+  "name": "test",
+  "main": "index.js",
+  "license": {
+    "type": "Apache-2.0",
+    "url": "https://opensource.org/licenses/apache2.0.php"
+  },
+  "scripts": {
+	  "build": "mkdir -p ./build && echo output > ./build/test && touch .env && cp .env ./build/"
+  }
+}

tests/stdlib/yarn/yarn.cue

@@ -0,0 +1,35 @@
+package yarn
+
+import (
+	"dagger.io/dagger"
+	"dagger.io/yarn"
+	"dagger.io/alpine"
+)
+
+TestData: dagger.#Dir
+
+TestYarn: {
+	run: yarn.#Script & {
+		source: TestData
+	}
+
+	test: #dagger: compute: [
+		dagger.#Load & {from: alpine.#Image & {
+			package: bash: "=5.1.0-r0"
+		}},
+		dagger.#Exec & {
+			mount: "/build": from: run
+			args: [
+				"/bin/bash",
+				"--noprofile",
+				"--norc",
+				"-eo",
+				"pipefail",
+				"-c",
+				"""
+					test "$(cat /build/test)" = "output"
+					""",
+			]
+		},
+	]
+}