diff --git a/action_test.go b/action_test.go
new file mode 100644
index 0000000..a599553
--- /dev/null
+++ b/action_test.go
@@ -0,0 +1,26 @@
+package spec
+
+import (
+	"bytes"
+	"strings"
+	"testing"
+
+	"github.com/rsteube/carapace"
+	"github.com/spf13/cobra"
+)
+
+func TestActionSpec(t *testing.T) {
+	cmd := &cobra.Command{}
+	carapace.Gen(cmd).PositionalCompletion(
+		ActionSpec("./example/example.yaml"),
+	)
+
+	var stdout bytes.Buffer
+	cmd.SetOut(&stdout)
+	cmd.SetArgs([]string{"_carapace", "export", ""})
+	cmd.Execute()
+
+	if !strings.Contains(stdout.String(), "sub1") {
+		t.Error("should contain sub1 subcommand")
+	}
+}
diff --git a/example/example.yaml b/example/example.yaml
index 77b3b05..048fa44 100644
--- a/example/example.yaml
+++ b/example/example.yaml
@@ -39,7 +39,7 @@ commands:
       optarg: ["first", "second", "third"]
     positional:
     - ["pos1A", "pos1B"]
-    - ["$files"]
+    - ["$files([.go, go.mod])"]
     - ["$directories"]
     - ["$(echo \"pos: $C_ARG0 flag: $C_FLAG_STYLED\")"]
     positionalany: ["posAny1", "posAny2"]
diff --git a/spec_test.go b/spec_test.go
index 5e1696f..78f5be2 100644
--- a/spec_test.go
+++ b/spec_test.go
@@ -37,6 +37,14 @@ func TestSpec(t *testing.T) {
 		t.Error(out)
 	}
 
+	if out := execute(t, example, "example", "sub1", "--env", "C_"); !strings.Contains(out, "C_CALLBACK=C_") {
+		t.Error(out)
+	}
+
+	if out := execute(t, example, "example", "sub1", "", ""); !strings.Contains(out, "action.go") {
+		t.Error(out)
+	}
+
 	if out := execute(t, example, "example", ""); !strings.Contains(out, "sub1") {
 		t.Error(out)
 	}