Fix #146

zio-cli/shared/src/main/scala/zio/cli/CliApp.scala

@@ -116,12 +116,12 @@ object CliApp {
       self.command
         .parse(prefix(self.command) ++ args, self.config)
         .foldZIO(
-          e => printDocs(e.error),
+          e => printDocs(e.error) *> ZIO.fail(e),
           {
             case CommandDirective.UserDefined(_, value) => self.execute(value)
             case CommandDirective.BuiltIn(x) =>
               executeBuiltIn(x).catchSome { case e: ValidationError =>
-                printDocs(e.error)
+                printDocs(e.error) *> ZIO.fail(e)
               }
           }
         )

zio-cli/shared/src/test/scala/zio/cli/CliAppSpec.scala

@@ -0,0 +1,53 @@
+package zio.cli
+
+import zio._
+import zio.test.Assertion._
+import zio.test._
+
+object CliAppSpec extends ZIOSpecDefault {
+
+  private val exitCodeSpec = {
+    sealed trait Subcommand extends Product with Serializable
+    object Subcommand {
+      final case class Make(int: BigInt) extends Subcommand
+    }
+
+    val makeCmd: Command[Subcommand] =
+      Command(
+        name = "make",
+        args = Args.integer
+      ).map(file => Subcommand.Make(file))
+
+    val exampleCmd: Command[Subcommand] = Command("example").subcommands(makeCmd)
+
+    def app(behavior: Task[Unit] = ZIO.unit) = CliApp.make(
+      name = "Grumpy",
+      version = "0.0.1",
+      summary = HelpDoc.Span.text("this is some doc"),
+      command = exampleCmd
+    ) { case Subcommand.Make(_) => behavior }
+
+    suite("exit code of the CLI")(
+      test("should exit with 0 when the command is successful") {
+        val result = app().run(List("make", "1"))
+
+        assertZIO(result.exitCode)(equalTo(ExitCode.success))
+      },
+      test("should exit with a code <> 0 when the parsing of the command fails") {
+        val result = app().run(List("make", "this is not an integer"))
+
+        assertZIO(result.exitCode)(equalTo(ExitCode.failure))
+      },
+      test("should exit with a code <> 0 when the command fails") {
+        val result = app(behavior = ZIO.fail(new RuntimeException("Boom"))).run(List("make", "1"))
+
+        assertZIO(result.exitCode)(equalTo(ExitCode.failure))
+      }
+    )
+  }
+
+  override def spec: Spec[TestEnvironment & Scope, Any] =
+    suite("CliApp")(
+      exitCodeSpec
+    )
+}